The paradigm contains five categories of information which can be obtained regarding a fraudulent prescription: (1) how the prescription form was obtained, (2) how the prescription was forged, (3) how it was passed, (4) how the forgery was detected by the pharmacist, and (5) how occasionally successful forgeries could have been detected. Fifty-four known fraudulent prescriptions from 1960 to 1983 were collected from pharmacists in an urban area. Analysis prescription blank and is forged completely by one person. The pharmacist's attention is immediately drawn to prescriptions for commonly abused substances such as tranquilizers. The pharmacist may attempt to contact the physician to verify the prescription. In other cases, the pharmacist determines a DEA control number which does not conform to the internal arithmetic code present in all genuine DEA numbers. In about two-thirds of the sample cases, pharmacists detected the fraud. For the remaining types of cases, pharmacists could be trained to recognize certain indicators, such as overly cautious, halting, corrected, or overwritten handwriting and printing/copying flaws. Other clues include the superfluous addition of 'M.D.' to the signature and cramping of letters. Procedures should be developed to protect prescription blanks from theft. Seven figures and 17 references are included.