How Does Voltarol Work? The active ingredient in Voltarol is Diclofenac Diethylammonium. Diclofenac belongs to group of medicines called NSAID'S (non-steroidal anti-inflammatory drug) which help to relieve pain & inflammation. Diclofenac blocks the action of a substance in the body called cyclo-oxygenase (COX). COX helps to produce certain chemicals in the body that include Prostaglandins. Prostaglandins are produced by the body in response to injury & certain conditions, they cause pain, inflammation & swelling. Diclofenac works by blocking the actions of these prostaglandins, reducing the discomfort & inflammation. How To Use Voltarol Emulgel Adults & children aged 14 & over; Apply a small amount & rub gently into the affected areas. Apply twice a day, preferably once in the morning & again in the evening. Voltarol should not be used for longer than 14 days unless recommended by a doctor. Do not use more than 50g of Voltarol in one week. Do not use Voltarol if you are asthmatic, are allergic to diclofenac, aspirin or any other NSAID's, if you have or have ever had hives (urticaria). If you are pregnant or breast-feeding or have had ever had a stomach ulcer. Do not use Voltarol at the same time as oral diclofenac tablets or any other NSAID tablets. Do not use on broken, cut or irritated skin.