I tried castor oil a few days ago and it didn't work

How many times can u try castor oil to induce labor?? I tried takin 1 and 1/2 half tablespoons a few days ago and it only gave me diarrhea and a few contractions later on that day . When I tried taking second dose a few hours later I threw it up immediately so basically that didn't even count . I was wondering should I try it again since by taking so little my body did respond . How many times can u try it ?