She said the drug marred this year's event, held on January 19, and it had effectively killed all hope of another happening.
"MDMA has ruined things for everyone."
And it was due to the high amount of drug use, drug trade and violence at this year's event she had "regrettably" decided the Boot Bash could no longer continue.
"It's gone. It was a party in a paddock and it was really good.
"It [drug use] is too big but I can't control it and it is only going to get worse."
The overdose was a factor, she said.
"It's a lot of resources for just one person.
"But people look to me and think 'you need to have these resources for this kind of thing' but that comes at a cost.
"I don't sell drugs and I don't do drugs so I can't be watching everyone."
A fight that resulted in a coward punch had further cemented her decision.
Attended by more than 200 people in the past, the event featured live music and the chance for singles to mix and mingle — with varying degrees of success.
One couple paired off and later married, Mills said.
She thanked those who had supported the Boot Bash over the past 10 years but gave a terse sign-off.
"To all the people whose selfishness has spoilt it for the others, you know who you are."
The Otago Daily Times is aware police did stop by the event but a police spokeswoman said an initial search in Beaumont on January 19 and 20 did not turn up anything related to the incidents.
However, a St John member of staff told the ODT the overdose and the assault required ambulances to attend and both people were flown by rescue helicopter to hospital.
