Fenbendazole (commonly referred to as Fenben or Panacur) –  is a benzimidazole class anthelmintic drug. It has been discovered and widely used since 1974 all over the world. (Ref.)

In the past couple decades it has been noted that fenbendazole and similar medications exhibited a measurable anti-cancer effect. (Ref.1, Ref.2)

This lead to speculations that this registered dog dewormer could be repurposed for use as complementary anti-cancer medicine. In truth, benzimidazole class drugs might work in a similar fashion as a wide range of modern chemotherapeutic drugs such as taxols and vinca alkaloids. (Ref.) The available toxicological information suggests that fenbendazole seems to be well tolerated in humans after oral exposure, however observations in humans are limited. (Ref.)

Under normal conditions, pure fenbendazole appears in powder form, whitish color and has poor solubility in water.

The medication has low reabsorbtion in the intestinal tract. Bioavailability can be improved by presence of food in the gut.