Abstract: Compositions which increase the bioavailability of proteinase inhibitors are disclosed. Compositions which include a pharmaceutically acceptable carrier comprising monoglycerides of medium chain-fatty acids are preferred. Preferred medium chain fatty acid glycerides include monoglycerides of saturated C.sub.6 to C.sub.12 fatty acids, preferably C.sub.8 to C.sub.10 fatty acids The pharmaceutically acceptable carrier preferably has an acid value of less than or equal to about 2.5. Preferably, the ratio of monoglycerides of medium chain fatty acid to the proteinase inhibitor is about at least 1.5.