As reported in later editions of yesterday's Evening Times, there are seven confirmed cases of E.coli O157.
NHS Greater Glasgow and Clyde (NHSGGC) said an initial probe suggested a possible link with burgers sold at food outlets in the arena.
The timeframe under investigation by the health board and Glasgow City Council's Environmental Health division - January 17-25 - includes shows by Top Gear, Del Amitri and Celtic Connections.
The £125million venue has a capacity of 12,000, meaning up to 84,000 people attended the Hydro in that period.
All seven people affected are recovering at home. One of the cases is from the NHSGGC area, two are from Lanarkshire, three from NHS Lothian and one is from Cumbria.
Dr Gillian Penrice, consultant in Public Health Medicine at NHSGGC, said: "While there is no conclusive evidence, our initial investigations have indicated that there may be a link to the consumption of burgers at the SSE Hydro and Glasgow City Council Environmental Health Officers are working closely with the vendors to ensure all appropriate food hygiene standards are being met.
"I would ask anyone who has attended the Hydro recently and who has experienced or is experiencing symptoms including stomach cramps, diarrhoea, nausea and fever to contact their GP."
A spokesman for the Hydro said they wanted to assure the public they had "no significant concerns in relation to catering".
She said: "We have been contacted by the Environmental Health in relation to an investigation into an E-coli outbreak they believe may have been connected to one of the catering outlets on our premises. We are awaiting further details to establish the exact cause of this isolated incident.
"The initial review of our caterers' standard procedures have been found satisfactory and Environmental Health have seen nothing in their processes which concerns them."