Effect of acetylsalicylic acid, paracetamol, and placebo on pain and blood loss in dysmenorrhoeic women.

The analgesic effect of paracetamol, acetylsalicylic acid, and placebo on dysmenorrhoea were compared in a double-blind crossover study of 30 women. There was a moderate placebo effect, but no significant difference was found between the three treatments. Blood loss was also measured and it did not vary with the type of drug ingested. It is concluded that paracetamol and acetylsalicylic acid in the doses used (0.5 g X 4 for 3 days) were not effective against heavy dysmenorrhoea, and that none of the drugs influenced the amount of blood lost.