The Public Health Office in the Northeast province has responded by rolling out a campaign on using cannabis responsibly.
Health Office pharmacist Cherdchai Ariyanuchitkul said treatment with cannabis should only go ahead under the supervision of medical staff.
He said people have also been advised to avoid recreational use of the drug, as this can result in a fine, imprisonment or both under the Public Health Act.
Recreational use of cannabis in public is still illegal.
Government and private hospitals in Khon Kaen will erect banners displaying information on the risks and the benefits of cannabis, he added.
Cherdchai said that the 100-plus people hospitalised were suffering side effects from cannabis they either smoked or consumed in food or beverages.
He added that most patients developed only mild symptoms, although one suffered mental health issues after smoking the drug.
Meanwhile, Bangkok authorities reported on Tuesday that four people had been admitted to hospital in the capital with suspected cannabis overdose and one later died of heart failure.
As of Tuesday, 21,432 people in Khon Kaen had registered to cultivate cannabis – 15,498 at home, 1,326 for medical use, 642 for commercial use and six for research.