Sussex Police used a pepper spray 12 times within eight weeks of it being introduced.
Officers drew the synthetic pepper Captor spray on 21 other occasions since it was introduced in April.
Its success means it could be available to all officers in Sussex before the end of the year.
The spray was introduced in Forest Division, which covers Crawley, Billingshurst and Steyning, after it was revealed assaults on officers had risen by 67 per cent last year.
Sussex Police were the first force in the country to pioneer the synthetic pepper spray which is already used in Germany, Switzerland, Holland and Belgium.
Chief Constable Paul Whitehouse said: "It is important to stress that Captor is intended as a defensive piece of equipment. It is not to control or punish but prevent greater violence."
The spray is an alternative to CS gas, which can cause unpleasant after-effects and does not work on everyone.
The force was one of only two nationwide to ban CS gas on the grounds that frequent exposure to it could damage officers' health.
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