Wellington-Dufferin-Guelph Public Health are warning people about white fentanyl after three people overdosed at Guelph's Consumption and Treatment Services site Wednesday.

Staff were able to reverse all three overdoses by using naloxone and oxygen.

Raechelle Devereaux, executive director of Guelph Community Health Centre, said the overdoses were a result of white fentanyl.

"The staff were beginning to notice it late last week as a new substance that was in our community and being brought into the site," she said.

Guelph's Consumption and Treatment Services is operated by the Guelph Community Health Centre and has had approximately 50 overdoses in the 14 months it has been operating.

"Three in one day, that's significant for the team to manage," she said.

Wellington-Dufferin-Guelph Public Health says white fentanyl has a similar consistency to icing sugar and is extremely potent.

Devereaux said staff at the site noticed those who used the drug had "atypical symptoms" such as muscle rigidity and clenching.

"Typically in an overdose you're seeing delayed breathing ... you're seeing somebody go into a state of non-responsiveness," she said.

"The challenge that was presented [on Wednesday] was that it actually required additional staff to be able to respond to the overdose."

Wellington-Dufferin-Guelph public health are reminding people to carry naloxone, not use drugs alone and to use the consumption and treatment services site to reduce the risk of an overdose.