The aim of this research was to study the pharmacokinetic characteristics of a slow-release 5-fluorouracil implant as well as to evaluate the clinical drug activity of this preparation in pancreatic cancer patients. Pharmacokinetic characteristics of the slow-release 5-fluorouracil implant were evaluated by examining the half-life time (T-1/2) and apparent volume of distribution (V-d) in pancreatic cancer patients; the slow-release 5-fluorouracil implant was administered through interstitial chemotherapy (tumor interstitium implantation). In the drug activity study, 36 locally advanced unresectable pancreatic cancer patients were divided randomly into an experimental treatment group (n=18) and a standard treatment group (n=18). The experimental treatment group was treated with interstitial chemotherapy of a slow-release 5-fluorouracil implant combined with systemic chemotherapy of gemcitabine; the standard treatment group was treated with systemic chemotherapy of gemcitabine. An internal drainage procedure was used when biliary and/or gastrointestinal tract obstruction occurred in the two groups. Clinical benefit response, including pain (visual analogue scale), analgesic drug use, general conditions (Karnofsky performance score), weight changes, and survival status, was observed. T-1/2 of the slow-release 5-fluorouracil implant was 5475.8 +/- 136.4min, whereas V-d was 45275.0 +/- 1028.6l. Clinical benefit response in the experimental treatment group was better than that in the standard treatment group. The experimental treatment group had longer median survival time compared with the standard treatment group. The slow-release 5-fluorouracil implant could deliver drugs mainly in the regional area of the tumor and prolong the drug action time; interstitial chemotherapy of a 5-fluorouracil implant combined with systemic chemotherapy of gemcitabine could improve the quality of life and survival status of pancreatic cancer patients. The method was promising and worthy of in-depth investigations.