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Botanical Description & Habitat

The Hop (Humulus Lupulus, Linn.) is a native British plant, having affinities, botanically speaking, with the group of plants to which the Stinging Nettles belong. It is found in most countries of the North temperate zone.

The English name Hop comes from the Anglo-Saxon hoppan (to climb).

The root is stout and perennial. The stem that arises from it every year is of a twining nature, reaching a great length, flexible and very tough, angled and prickly, with a tenacious fibre, which has enabled it to be employed to some extent in Sweden in the manufacture of a coarse kind of cloth.

The leaves are heart-shaped and lobed, on foot-stalks, and as a rule placed opposite one another on the stem, though sometimes the upper leaves are arranged singly on the stem, springing from alternate sides. They are of a dark-green color with finely toothed edges.

The flowers spring from the axils of the leaves. The Hop is dioecious, i.e. male and female flowers are on separate plants. The male flowers are in loose bunches or panicles, 3 to 5 inches long. The female flowers are in leafy cone-like catkins, called strobiles.

Only female Hop plants are used in brewing.

Historical Properties & Uses

We find the Hop first mentioned by Pliny, who speaks of it as a garden plant among the Romans, who ate the young shoots in spring, in the same way as we do asparagus, and as country people frequently do in England at the present day.

Hops appear to have been used in the breweries of the Netherlands in the beginning of the fourteenth century. In England they were not used in the composition of beer till nearly two centuries afterwards.

A pillow of warm Hops will often relieve toothache and earache and allay nervous irritation.

Hops have been used through the centuries as a mild sedative and sleeping aid. Attempts to discover the herb's active principles, or even to verify its sedative effect experimentally, were frustrated for many years, but good experimental procedures finally produced confirmation of its sedative action. Apparently, hops' active principles are extremely unstable, and efforts to process the herb during early stages of the experiments effectively destroyed them. Undoubtedly, normal commercial processing also destroys much of the herb's activity.

Hop's primary use is to calm nerves and induce sleep. For these purposes it is usually combined with other herbal sedatives, i.e., passion flower, valerian root, and skullcap. As a sleeping aid, hops have been put in pillows and used in teas. Hops have antispasmodic and antibiotic action, and are often used as a stomachic; the herb also contains estrogenic substances. In homeopathy, a fresh tincture is used as a narcotic, diuretic, and aphrodisiac, but these uses have not been validated.

This herb has approval status by the German Commission E for anxiety, mood disturbances and sleep disturbances e.g insomnia.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Method of Action

Hops have sedative action
The sedative property of hops eluded researchers for many years, suggesting the active principle may be extremely volatile and short-lived. Nevertheless, its sedative action was eventually found and has since been further substantiated. Its sedative action does not depend on muscle relaxation, but instead is a function of the central nervous system. Generally, a soothing, relaxing calm is experienced within 20-40 minutes after ingestion of the herb. Lupulin is thought to be the active ingredient, though at least one study found sedative properties in a lupulin-free preparation.

The dose-response relationship is as follows: small doses are sedative; moderate doses are hypnotic; large doses are paralyzing.

An active sedative constituent of hops, 2-methyl-3-buten-2-ol, is structurally similar to a known sedative, methylpentynol. In an open field test in rats, both chemicals were effective within the same range. Motility tests combined with the "Chimney-Test" demonstrated a decrease in motility with hops compound could not be ascribed to a muscle relaxing effect. It remains to be determined if the hops compound is present in proprietary preparations, most of which have undergone some sort of oxidation. Meanwhile, it is known the hops compound, due to its water solubility, is enriched in the more volatile fraction of hops, and extracts obtained by steam-distillation are relatively low in the active principle.

Hops have spasmolytic principles
In an investigation of hops' spasmolytic effects, the herb exerted a strong spasmolytic effect on smooth muscle preparations of rabbit jejunum, guinea pig duodenum, and rat uterus; it antagonized the spasmogenic effects of acetylcholine, atropine, papaverine, mepoyramine, and histamine. This action was produced by a double mechanism, both neurotropic and musculotropic, but the musculotropic element was much stronger. These findings would seem to justify the use of hops in the treatment of gastric and intestinal spasms. Hops also exhibited antihistamine and antioxytocic effects.

Hops are used in sleeping aids
Hops is a constituent (along with valerian, melissa, and passion flower) of a proprietary sleeping aid called Vita-Dor, which is marketed in Germany. This product was recently submitted to clinical trial and found to be very effective in a dose-dependent manner. Age was important; generally, patients over sixty required less. It was impossible to determine how much of its effect was due to the individual components of the drug.

Hops have antibiotic properties
Lupulone and humulone, components of hops, inhibit the growth of acid-fast or gram positive organisms in a dilution of 1:100,000, making these substances some of the most powerful known among the higher plants. Lupulone and hupulone have also been found effective, in a range similar to that of streptomycin, against infection produced by M. tuberculosis in mice. Other hops constituents, including isohumulone and humulinic acid, are also bacteriostatic. The inhibitory action was due to the induction of primary membrane leakage, which led to complete inhibition of active transport of several amino acids into whole bacteria and isolated membrane vesicles.

Hops may be estrogenic
Hops bitters are held to be estrogenic, but research results are conflicting. The final answer awaits further investigation.

Drug Interactions & Precautions

Lupulin is official both in the British Pharmacopoeia and the United States Pharmacopoeia.

Known Interactions
As a diuretic herb, hops may potentiate the action of antihypertensive, ganglionic, or peripheral adrenergic blocking drugs, tubocurarine, and to a lesser degree, norepinephrine.

Hops have been shown to antagonize the spasmogenic effects of acetylcholine, atropine, papaverine, mepyramine, and histamine.

Possible Interactions
Any of the following drugs may be imperfectly absorbed if hops are being used on a daily basis: tetracycline derivatives, oral anticholinergics, phenothiazines, digoxin, isoniazid, phenytoin, and warfarin.

The use of diuretic herbs such as hops may require dosage adjustments of antidiabetic drugs. The diuretic action of this herb may also reduce renal clearance of lithium.

In addition, the urinary excretion of alkaline drugs, such as amphetamines or quinidine, may be inhibited by the antacid nature of hops. The antacid nature of hops may also decrease or delay the absorption of nalidixic acid and the sulfonamides.

Hops' analgesic effects may be additive with other analgesics and anesthetics; conversely, they may be inhibited by barbiturates, despite any CNS-depressant effects which may occur.

The analgesic property of hops may be reversed or even eliminated by P-chlorophenylalanine, cyproheptadine HCl, and phenobarbital. It should be noted the CNS-depressant tendency of this analgesic may be potentiated by chlorpoxthixene HCl, haloperidol, and tranquilizers.

The presence of estrogen-like substances in hops may increase the production of procoagulant factors which, in turn, may inhibit the anticoagulant action of heparin or coumarin. The estrogenic constituents of the plant may also potentiate oral antidiabetics, folic acid antagonists, and some corticosteroids. However, the presence of estrogen can, by inducing hyperlipemia, inhibit antihypercholesterolemics. The herb can inhibit the activity of most parenteral medications by reducing the rate of spreading.

The estrogenic activity of this herb may be inhibited by meprobamate and phenobarbital. Due to the presence of estrogenic substances, oxytocin may augment the neural conductivity and activity of uterine smooth muscle, and raise blood glucose levels enough to alter insulin requirements in diabetics.

Prolonged use of this diuretic herb may affect certain laboratory test results, such as electrolytes (especially potassium and sodium), blood urea nitrogen (BUN), uric acid, glucose, and protein bound iodine (PBI).

It should also be noted hops' antacid properties may enhance the renal tubular resorption of the antiarrhythmic drug, quinidine, leading to increased quinidine serum levels.

To the extent this herb's action depends on the presence of cholinergic substances, it will be affected by the decrease in cholinergic-receptor stimulation produced by anticholinergics.

In the absence of other hard data, it may be assumed observable interactions occur between the many central nervous system drugs and the psychoactive principles in hops.

There is evidence which shows combined use of bactericidal and bacteriostatic agents will lower the effectiveness of the bacteriostatic agent. How this finding applies to herbal anti-infectives is still unknown.

Safety Factors & Toxicity

Large doses are not well-tolerated.

Hops may cause contact dermatitis in sensitive individuals.

Smoking hops as a marijuana substitute may be dangerous, as little is known about the effects of smoking this plant.

This herb has approval status by the German Commission E.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Preparation & Administration

The official preparations are an infusion and a tincture. The infusion is employed as a vehicle, especially for bitters and tonics: the tincture is stomachic and is used to improve the appetite and digestion. Both preparations have been considered to be sedative, were formerly much given in nervousness and hysteria and at bedtime to induce sleep; in cases of nervousness, delirium and inflammation being considered to produce a most soothing effect, frequently procuring for the patient sleep after long periods of sleeplessness in overwrought conditions of the brain.

Three times a day

Dried strobile (fruiting structure resembling a pinecone)
0.5-2 grams

made from 1/2 tsp dried strobile

Fluid extract
1:1 in 45% alcohol, 0.5-2 ml

1:5 in 60% alcohol, 1-2 ml
Apply tincture locally for antimicrobial action

This herb has approval status by the German Commission E.

Recommended daily dosages in Germany are as follows:

0.5 g of the herb.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.


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Humulus Lupulus

American Hop

? Southwest School of Botanical Medicine