The effects of mebendazole and fenbendazole on Trichinella spiralis in mice.

Oral administration of either Mebendazole or Fenbendazole at 50 mg/kg body weight was effective in killing a 7-hr Trichinella spiralis infection in mice. Adult worms, 72 hr postingection, were unaffected by the same dose of Fenbendazole, while Mebendazole showed partial activity. Both Mebendazole and Fenbendazole were active against developing muscle larvae. Mebendazole was effective against encysted muscle larvae while 50 mg of Fenbendazole per kg per day for 7 days from 28 days postinfection failed to have any effect on this stage of the life-cycle.