You should not use it too often and you should not cover the treated area with a bandage or plaster. It is a safe medicine with few side effects, but you may get a skin rash, itching, reddening or burning of the skin.
Occasionally a skin rash may be a sign of severe allergic reaction. Tell your doctor straight away if you get a rash with blistering. Jonac Gel is not recommended if you are pregnant or breastfeeding and you should not use it if you are already taking diclofenac (or other similar) tablets.