Background: Clove essential oil has anti-inflammatory activity because of it contains high levels of eugenol. Development of dosage forms already done so it is necessary to evaluate it. Objective: The aim of this study is to determine the effect of variations concentration of chitosan as a gel base to the viscosity of gel and skin irritation effect. Clove essential. Materials and Methods: . Clove essential oil is formulated in 4% and 5% concentration of chitosan as gel base. Hydrogel contains with clove essential oil 3.75 grams, tween 80 4.67 gram, propylene glycol 2.33 gram and chitosan 14,234 gram. Besides viscosity and skin irritation, other characteristic like pH, spreadibility and stickiness was verified with previous research. Results: The result of viscosity measurement show that formula 2 given good viscosity, there is 1.447 Pa.s. Skin irritation study show that hydrogel of clove essensial oil does not cause irritation in rabbit’s skin. Data analysis with One Way ANOVA and Mann-Whitney show no significant differences, because P>0.05 for the verification of pH, spreadibility and stickiness. The best formula of clove essensial oil hydrogel is formula 1 with  contains clove essensial oil 3,106 gram, tween 80 5,078, propylene glycol 2,540 gram, and chitosan base 4%. The result showed that clove essensial oil hydrogel with chitosan base is safe and be able to applicate as a topical anti-inflammatory