Basically solid “liquid” paraffin. (at room temperature solid and body temperature very slippery). Helps passage of stool in constipated states, but its main use is in helping eliminate hair balls in cats. Fur/Hair balls are a very common cause of vomiting in cats and katalax is a very civilised way of giving cats “liquid” paraffin. It has a flavour most cats do not mind and beats the hell out of giving cats liquid paraffin!