Hi and welcome to HCM. Their are many indications for using Flagyl tab if u are suffering from Trichomonas vaginalis, In this condition along with patient asymptomatic sexual partners of treated patients should be treated simultaneously if the organism has been found to be present, in order to prevent reinfection of the partner. if u are given these tabs for some other condition, then no need to avoid sexual intercourse. The best person to decide is your treating doctor, as he knows your medical history completely. I advice u to consult him for further clarifications. All the best Regards Dr Santosh