Two animal rights campaigners were arrested after a protest outside a greyhound racing arena in Somerset.
Police were called to the Abbey Moor stadium in Glastonbury on Tuesday after reports of attacks on a campaigner.
Gina Harris, spokeswoman for Avon & Somerset Greyhound Action, said she had been hit by a dog trainer and protest boards were thrown in a nearby river.
Two campaigners who were arrested on public order offences were later released without charge.
The Avon & Somerset Greyhound Action campaigners had been distributing leaflets urging people to boycott greyhound racing.