Have used both ivermectin and fenbendazole. They are both effective but I advise care in the use if ivermectin. Fenbendazole is without side effects when used reasonably in accord with recommended dosages. I found that ivermectin may have significant side effects. So, basically I think it's a good effective drug but be cautious with it because it's powerful. It's method of action is very different from fenben. I believe Ivermectin works as a nerve poison. A little goes a long way. Advise thorough reading on side effects. Safe and effective when used correctly.