Contraception

Mexican yam

Dioscorea mexicana

Not a use of the plant itself: diosgenin from Mexican yams was the raw material from which Syntex chemists (Rosenkranz, Djerassi, Miramontes) synthesised norethindrone in 1951, a potent oral progestogen that became the most widely used progestin in contraceptive pills; the same feedstock gave an economical synthesis of cortisone.

Upland cotton

Gossypium hirsutum

As a male contraceptive, gossypol stopped sperm production in most of the more than 8,800 Chinese men tested, with over 90% efficacy in preventing pregnancy. It was abandoned because spermatogenesis did not fully recover in 10–20% of men (over 20% in one review) and about 1% developed low potassium, some with paralysis. Effective, but not acceptably safe.

Chinese hibiscus

Hibiscus rosa-sinensis

Ayurvedic literature attributes antifertility activity to the plant. Ethanolic root extract at 400 mg/kg completely prevented embryo implantation in rats and had oestrogen-like effects on the uterus; flowers have shown anti-implantation and antispermatogenic activity. Not tested or suitable as a human contraceptive.

Flame of the forest

Butea monosperma

The seed is a folk contraceptive. Butin, a flavonoid from the seed, stopped embryos implanting in 40–90% of pregnant rats, depending on dose, and acted as a weak oestrogen. Animal data only; this is a reason for caution, not a recommendation.

Green cestrum

Cestrum parqui

A leaf extract (40–250 µg/ml) immobilised and damaged human sperm in the test tube in a dose- and time-dependent way. This is a single laboratory study; the plant is toxic and has never been tested as a contraceptive in people.

Kamala tree

Mallotus philippensis

Kamala is recorded as a traditional oral contraceptive. A seed extract lowered FSH and LH and impaired ovulation and pregnancy in female rats; this is a reason for caution, not a usable method.

Prickly chaff flower

Achyranthes aspera

Widely used for fertility control in Ethiopian local medicine. Animal studies reviewed in 2021 report anti-implantation, abortifacient and spermicidal effects. In pregnant rats a leaf extract (1000 mg/kg) reduced implantation, slowed embryo growth and raised fetal deaths. This shows harm to the fetus, not a safe or reliable contraceptive.

Soapnut

Sapindus mukorossi

Reetha saponins immobilised all human sperm within 20 seconds at 0.05% in vitro and damaged sperm membranes under the electron microscope; combined with neem extract and quinine they were proposed for a vaginal contraceptive. No efficacy trials were found in the sources fetched, and it should not be relied on to prevent pregnancy.

Wild carrot

Daucus carota

Romans and Greeks used the seeds for contraception and as an emmenagogue; a Native American recipe for female contraception included them. Several rat studies found seed extracts or the seed oil interfered with early pregnancy (anti-implantation, anti-progestogenic and anti-oestrogenic effects). There are no human studies, effectiveness is unknown, and it is not a reliable contraceptive.

Zoapatle

Montanoa tomentosa

Used as a contraceptive and to induce abortion in early pregnancy. In six women in early pregnancy given leaf decoctions (1.0–1.4 g dry leaf/kg/day for 2 days) before a planned abortion, all had cramps and cervical dilatation, and four bled. In rats the extract interfered with embryo implantation.

Indian hemp

Apocynum cannabinum

Okanagan-Colville women are recorded taking a root decoction during menstruation to become permanently sterile. No evidence of effect or safety exists.

Violet tree

Securidaca longepedunculata

A review of African women's health remedies records its use for contraception in South Africa, and in Benin as a drink during pregnancy for 'strengthening'. Given its toxicity, both uses carry serious risk.