Acetylsalicylic acid (ASA)--now the most potent platelet-aggregation inhibitor--is being investigated in combination with glycine (Godamed; text preparation A) and microencapsulated (test preparation B) in view of the plasma total salicylate level and platelet aggregation inhibiting effect. The examination is conducted on 20 patients by the cross-over method. An increase of the plasma total salicylate level of test preparation A compared with test preparation B is highly significant up to 60 min after application of 1000 mg ASA respectively. As in shorter time a higher plasma total salicylate level is reached a significantly higher analgesic effect of the test preparation A may be expected. In certain indications, occurring with pain, as for instance arterial occlusive disease, thrombophlebitis, etc., this is absolutely desired. Additional application of analgetics is then often unnecessary. A differentiated use of ASA preparations as platelet-aggregation inhibitors is therefore required. To investigate the disaggregating effect of both ASA preparations the PAT-III test by Breddin was used. 2 h after the oral application of 1000 mg ASA a complete normalisation by both ASA preparations was reached, whereas before a significant higher platelet aggregation had been recognized. The somewhat faster reached effect of test preparation A is not significant and clinically not relevant. When in the acute phase as well as in the long-term treatment of the above mentioned indications an ASA-containing platelet-aggregation inhibitor is used, that preparation should get preference which is well tolerable and has the same platelet-disaggregating effect but with the higher analgesic effect.