[10][11] It is taken by mouth when used to prevent gastric ulcers in people taking nonsteroidal anti-inflammatory drugs (NSAID).

It acts upon gastric parietal cells, inhibiting the secretion of gastric acid by G-protein coupled receptor-mediated inhibition of adenylate cyclase, which leads to decreased intracellular cyclic AMP levels and decreased proton pump activity at the apical surface of the parietal cell.

Misoprostol is sometimes coprescribed with NSAIDs to prevent their common adverse effect of gastric ulceration (e.g., with diclofenac in Arthrotec).

Misoprostol-induced diarrhea and the need for multiple daily doses (typically four) are the main issues impairing compliance with therapy.

[33] The World Health Organization (WHO) provides clear guidelines on the use, benefits and risks of misoprostol for abortions.

It is not inherently unsafe if medically supervised, but 1% of women will have heavy bleeding requiring medical attention, some women may have ectopic pregnancy, and the 12% of pregnancies that continue after misoprostol failure are more likely to have birth defects and are usually followed up with a more effective method of abortion.

[45] The use of rectally administered misoprostol is optimal in cases of bleeding; it was shown to be associated with lower rates of side effects compared to other routes.

[46][47] However, it is inexpensive and thermostable (thus does not require refrigeration like oxytocin), making it a cost-effective and valuable drug to use in the developing world.

[48] A randomised control trial of misoprostol use found a 38% reduction in maternal deaths due to post partum haemorrhage in resource-poor communities.

However, due to a higher rate of adverse effects, routine use of misoprostol for this purpose in other women is not supported by the data.

[citation needed] There is limited evidence supporting the use of misoprostol for the treatment of trigeminal neuralgia in patients with multiple sclerosis.

[53][54] The most commonly reported adverse effect of taking misoprostol by mouth for the prevention of stomach ulcers is diarrhea.

[55] The next most commonly reported adverse effects of taking misoprostol by mouth for the prevention of gastric ulcers are: abdominal pain, nausea, flatulence, headache, dyspepsia, vomiting, and constipation, but none of these adverse effects occurred more often than when taking placebos.

[42] The study concluded that sublingually administered misoprostol dosed at 600 μg or 400 μg had greater instances of fever and diarrhea due to its quicker onset of action, higher peak concentration and bioavailability in comparison to vaginal or oral misoprostol.

[58] Because the complications are rare, it is difficult to determine if misoprostol causes a higher risk than do other cervical ripening agents.

[59] It is recommended that medical treatment for missed abortion with misoprostol should only be considered in people without the following contraindications: suspected ectopic pregnancy, use of non-steroidal drugs, signs of pelvic infections or sepsis, unstable hemodynamics, known allergy to misoprostol, previous caesarean section, mitral stenosis, hypertension, glaucoma, bronchial asthma, and remote areas without a hospital nearby.

[63] The American College of Obstetricians and Gynecologists holds that substantial evidence supports the use of misoprostol for induction of labor, a position it reaffirmed in response to the Searle letter.

[21] A vaginal form of the medication is sold in the EU under the names Misodel[65] and Mysodelle[66] for use in labor induction.

[medical citation needed] Misoprostol is used for self-induced abortions in Brazil, where black market prices exceed US$100 per dose.