THERE HAVE BEEN TWO GENERAL APPROACHES TO LOCATING ILLICITLY PRODUCED DRUGS. THE FIRST ATTEMPTS TO RELATE SEIZURES FROM DIFFERENT LOCATIONS ON THE BASIS OF A SPECIFIC FEATURE, SUCH AS A TABLET MANUFACTURING DEFECT OR MULTICOMPONENT FINGERPRINT PATTERNS. THE SECOND IS DESIGNED TO DERIVE INFORMATION REGARDING THE MANUFACTURE OF ILLICIT DRUGS, FOR EXAMPLE, BY IDENTIFYING SPECIFIC RESIDUAL COMPONENTS AND ESTABLISHING THE CHEMICALS, EQUIPMENT, AND EXPERTISE REQUIRED FOR PRODUCTION. PHYSICAL ANALYSIS OF ILLICIT DRUGS IS LARGELY LIMITED TO TABLETS AND CAPSULES. THE MAJORITY OF MULTICOMPONENT FINGERPRINT PATTERNS IN CHEMICAL ANALYSIS HAVE BEEN OBTAINED BY GAS CHROMATOGRAPHY. WITH ANY MULTICOMPONENT COMPARISON TECHNIQUE, HOWEVER, THE POSSIBILITY OF CHANGING PATTERNS DUE TO VARYING CONDITIONS OF STORAGE AND/OR HANDLING IS ALWAYS PRESENT. ATTEMPTS TO OBTAIN INFORMATION ON CHEMICALS EMPLOYED IN AND EXPERTISE REQUIRED FOR ILLICIT DRUG PRODUCTION HAVE BEEN PRIMARILY CONCERNED WITH THE DETERMINATION OF IMPURITIES IN SEIZED AMPHETAMINE AND METHYLAMPHETAMINE SAMPLES. AN ALTERNATIVE CHEMICAL APPROACH TO EVALUATING DRUGS IS THE ANALYSIS AND COMPARISON OF EXCIPIENTS, SUCH AS BULKING AGENTS. CHEMICAL COMPOUNDS FREQUENTLY APPEARING AS EXCIPIENTS ARE SUGARS. REFERENCES AND ILLUSTRATIONS OF SAMPLE CHEMICAL ANALYSIS TECHNIQUES ARE PROVIDED. (DEP)