The absorption of zinc in different parts of the small intestine and from various Zn compounds was studied in situ, using rats. Segments of equal length from the duodenum, jejunum and ileum were ligated. Into these loops, 65Zn-ZnCl2 or 65Zn-ZnCl2 with an excess of histidine at a molar ratio of 1:250 and 1:2,000 was injected. The uptake of 65Zn was measured in blood, plasma and different organs after 1 h of absorption. The absorption of zinc was significantly greatest from the duodenum, followed by the jejunum and ileum. The jejunum differed only slightly from the ileum in the absorption capacity for zinc. A 250-fold excess of histidine did not alter the Zn absorption in comparison to ZnCl2. There were, however, distinct interactions between the site of Zn absorption and the Zn compound at the molar ratio of zinc:histidine of 1:2,000. With this addition of excess histidine, zinc was absorbed just as well from the jejunum as from the duodenum. The 2,000-fold addition of histidine raised the Zn absorption from the jejunum by about 40 % in comparison to ZnCl2.