Common names: Hemp seed, hemp fruit, huo ma ren
Botanical names: Cannabis sativa, Cannabis
© Martin Wall
Parts used and where grown
Hemp is a form of the same plant as marijuana that generally has much lower levels of the
psychoactive cannabinoid compounds. The seed and seed oil have probably been used for food,
cooking, and lamp oil in Asia and North Africa for millennia. Hemp is believed to come from
China. The nutty seeds normally have a hard shell which has to be removed to make it edible.
Today, in order to be legal in most countries, the seeds must be treated so that they cannot
be planted and grown.
Shelled hemp seed has been
used in connection with the following conditions (refer to the
individual health concern for complete information):
Historical or traditional use (may
or may not be supported by scientific studies)
Hemp is known from archeological and historical records to have been used for a very long
time for making fiber for clothing and ropes. The edible seeds and oil expressed from the
seeds are noted in ancient Chinese medicine for their medicinal effects as well. Known as huo
ma ren (literally “fire hemp seed”), hemp seed is used primarily for alleviating
constipation as a bulk-forming laxative.1 Hemp is also mentioned in ancient
Egyptian medical texts such as the Ebers papyrus as well as other places for use in making
Hemp seeds contain oil that is relatively rich in essential fatty acids. In particular,
hemp oil is a source of both the omega-3 fatty acid alpha-linolenic acid (ALA) and the omega-6
fatty acid gamma-linolenic acid (GLA). A tablespoon of seeds generally contains 3 to 4 grams
of total fat, of which 70% are polyunsaturated fats and as much as 15 to 20% are
ALA.3 GLA content is generally much lower at roughly 2 to 5%. ALA and GLA and other
plants that contain one or both of these substances, such as flax,
borage, evening primrose, and black
currant, are known or strongly believed to have benefits for a variety of inflammatory
conditions, atherosclerosis, and some neurological problems. However, the benefits of hemp
seed for any of these issues has not been studied. Hemp also contains natural vitamin E and a significant amount of
An unidentified compound or compounds from an extract of hemp seeds has been shown to
promote memory, learning, and immune function in mice.5 6 It is believed
to act by stimulating a brain enzyme known as calcineurin.
Hemp seeds contain cannabinols such as delta-9-tetrahydrocannabinol (THC), the psychoactive
compounds found in marijuana leaves, flowers, and seeds. The levels are generally
significantly lower than those found in marijuana products, and most tests have found that
volunteers fed even large amounts of shelled hemp seed or oil do not have psychological
effects and do not have positive urine tests for marijuana.7 8 However,
some reports have found that some people can develop sufficient levels of THC metabolites in
their urine that they would be considered to have smoked marijuana.9
How much is usually taken?
Typically 1 tablespoon (15 grams) of shelled hemp seed is taken twice per day.
Are there any side effects or interactions?
For most people there are no side effects, except sometimes loosening of the stool.
However, some people may experience hallucinations or euphoria if they are particularly
sensitive to THC or if they happen to use a brand that has somewhat higher THC levels. As the
oils in hemp seed are known to inhibit platelets, anyone taking hemp seed oil with
anticoagulant drugs should be aware that there is a theoretical possibility that bleeding
At the time of writing, there were no well-known drug interactions
with shelled hemp seed.
1. Chen JK, Chen TT. Chinese Medical Herbology and Pharmacology.
City of Industry, CA: Art of Medicine Press, Inc., 2003.
2. Nunn JF. Ancient Egyptian Medicine. Norman: University of
Oklahoma Press, 1996:156.
3. Fitzsimmons S. Hemp seed oil: Fountain of youth? Br J
4. Odani S, Odani S. Isolation and primary structure of a methionine- and
cystine-rich seed protein of Cannabis sativa. Biosci Biotechnol Biochem
5. Luo J, Yin JH, Wei Q. The effect of calcineurin activator, extracted
from Chinese herbal medicine, on memory and immunity in mice. Pharmacol Biochem Behav
6. Luo J, Yin JH, Wu HZ, Wei Q. Extract from fructus cannabis activating
calcineurin improved learning and memory in mice with chemical drug-induced dysmnesia.
Acta Pharmacol Sin 2003;24:1137–42.
7. Leson G, Pless P, Grotenhermen F, et al. Evaluating the impact of hemp
food consumption on workplace drug tests. J Anal Toxicol 2001;25:691–8.
8. Steinagle GC, Upfal M. Concentration of marijuana metabolites in the
urine after ingestion of hemp seed tea. J Occup Environ Med 1999;41:510–3.
9. Fortner N, Fogerson R, Lindman D, et al. Marijuana-positive urine test
results from consumption of hemp seeds in food products. J Anal Toxicol