Labor was induced in a group of 200 women in 2nd trimester of pregnancy by crystal trichosanthia injected into the amniotic cavity. It was effective and the success rate was 99.5%. The average abortion inducing interval was 4.69 days porm 1.15 days. Blood loss was scanty during labor in 90.5% cases, being less than 100 ml. There was only 1 case suffering laceration of cervix. The side effects of crystal trichosanthin were dramatically reduced with the simultaneous use of betamethason intramuscularly for 3 successive days. Side effects were reduced because the drug was concentrated in the cavity and only a little was present in the blood stream and, what's more, the anti-allergic action of betamethason was effective. Trichosanthin is a kind of plant protein so it will possibly cause allergic reaction, which can induce the production of antibodies that will influence the effect of its reinjection.