A new computer program in Fortran II (with Format) for the equation, C = a 0 k a V d ( k a − k d ) ⋅ ( e − k d t − e − k a t ) , has been written. This program overcomes the problems of the previous programs published. A grid method was used to search for the constants and a method to handle exponential overflow was included. Applicability of the equation and the computer program was demonstrated on the IBM 1410 computer system with eight different sets of data from the literature. The data represented a variety of drugs, i.e., sulfaethylthiadiazole, aspirin alone or with additives, oxazepam, penicillin salts, and trimeprazine, in a variety of dosage forms. The conclusions of the authors were verified by the calculated constants. In some instances the conclusions of the originators of the data could be expanded by the use of the calculated constants.