Experts are trying to get to the bottom of an illness that hit at least 15 guests at a wedding reception, the Health Protection Agency (HPA) said.
Possible causes for the sudden sickness at the JCB Lakeside Club in Rocester, Uttoxeter, Staffordshire, on Friday night include food poisoning and norovirus, a spokeswoman said.
Paramedics were called to the social club at about 11.40pm on Friday after a number of people suddenly fell ill.
A spokeswoman for the HPA, which is investigating, said 15 people were found to be suffering sudden onset of symptoms including diarrhoea and vomiting.
Four were taken to hospital but discharged the same night, she said.
She added samples had been taken and they were looking into whether the sickness was caused by food poisoning or norovirus.
"There were 15 people taken ill and the West Midlands Ambulance Service went out to this wedding party at the social club," she said.
"Four of them were taken to hospital but they were discharged the same evening.
"We managed to get samples from two of them and if we manage to grow cultures off them we will hopefully have the results from that by about Tuesday.
"We don't know at this stage whether it's food poisoning or norovirus."