Zpack is a natural fish antibiotic. It has been used in Europe since the 1960s, and can be found in Japan, Korea and China. It is effective against a wide range of bacteria, and is often used to treat serious infections. The fish antibiotic is based on the science that fish have a higher content of a natural antibiotic called erythromycin. The antibiotic is a brownish color and can be used as the raw material to make food. The fish antibiotic claims that it is safe for human consumption. However, there are some people who are worried about the use of erythromycin. In order to help alleviate the concerns about Zpack, the brand has announced that the antibiotic is not used as a food additive. There are also regulations that regulate use of erythromycin as a food additive.