Hope Stansbury was scared of rats and at her request was given a fake one to handle instead.
After shooting the new sequences, Andy Milligan had a hard time getting rid of the rats, so he created an ad campaign offering free live rats to theatergoers.
Originally filmed on location in England as "The Curse of the Full Moon" with a running time of 72 minutes. Andy Milligan's producer William Mishkin said that the running time was too short and more footage had to be added in. Due to the success of Calafrio (1971), Milligan added in the story of man-eating rats and shot the footage in his hometown on Staten Island in and on the steps of his very house. The new sequences increased the running time to a full 92 minutes.
Due to the tight low budget, director Andy Milligan appeared in two different roles in the film under two different aliases. One playing a pawnshop owner named Mr. Micawber who handles the rats for Monica. The other role is of a gunsmith who offers to melt down silver bullets for Diana's request.