T ooth extraction is one kind of action that often cause complication. Complication can minimalize by accelerate the process of wound healing. Fibroblast and collagen cells has an important role in the process of wound healing. Avocado seed (Persea americana Mill.) contains substance that can increase the formation of fibroblast and collagen cells in wound healing process. The aim of this research is to determine the effect of avocado seed extract to increase the number of fibroblast and collagen cells after tooth extraction. The research method use is in vivo experimental laboratoric with the design methods post test only control group design. This study used forty eight rats that divided into three groups, consist of control group, treatment groups that were given avocado seed extract concentration 50% and treatment groups that were given avocado seed extract concentration 90%. Observation were made in day-3, day-5, day-7 and day-14 after tooth extraction by sacrificing rats and make histological preparation. The statistical use Kruskal Wallis and Mann Whitney test. The statistical tests indicate there are effects of avocado seed extract to increase the number of fibroblast cells and collagen between three different groups (p <0.05). There is very strong correlation in fibroblast and collagen cells in tooth socket. The conclusion of this research is avocado seed extract can increase the number of fibroblast cells and collagen in the tooth socket after extraction.