In this hair analysis, the authors attempted to discern if there are pathways in hair fiber by which small organic molecules like morphine, codeine, and dihydrocodeine leave or enter the fiber. Diffusion experiments were performed using natural and predamaged clipped hair fibers as diffusion bridges and aqueous solutions of morphine, codeine, and dihydrocodeine. The test series were conducted at ambient temperature and at high humidity. After 312 or 372 hours the middle segments of the strands were clipped, washed, and analyzed by GC/MS. Only when virgin hair samples were used did the solutes pass along the fiber at full length resulting in a positive immunological finding at the end of the diffusion bridge. Most of the washing fluids were positive for opiates. All centerpieces had a high opiate content. The opiate concentration in damaged hair was significantly higher. The authors concluded that the morphology and the physicochemical properties of the hair fiber are indispensable for a valid interpretation of the results of drug analysis in hair. Figures, tables, references