Trump argued that Clinton was more energetic during the beginning of their debate last Sunday, but lost her steam by the end of the debate. He offered no evidence to back up his wild claim.
"I think we should take a drug test prior to the debate," Trump said during a rally here. "Because I don't know what's going on with her, but at the beginning of her last debate, she was all pumped up at the beginning, and at the end it was like, huff, take me down. She could barely reach her car."
Trump appeared to be conflating the debate with last month's 9/11 ceremony where Clinton struggled to get inside her van on her own due to a bout with pneumonia.
Reached for comment, the Clinton campaign said Trump is trying to depress voter turnout by his "shameful attempts to undermine an election weeks before it happens."
Trump has repeatedly questioned Clinton's "strength and stamina," raising concerns about her physical and mental fitness to be president -- all without providing any evidence for his claims.
But Trump's suggestion that Clinton has been taking drugs in order to perform well at the presidential debates is a new step for him.
"A lot of things are going on, folks. A lot of things. I think she's actually getting pumped, you want to know the truth? She's getting pumped up," Trump said Saturday. "She's getting pumped up for Wednesday."
Trump added that presidential candidates are "like athletes" and should undergo drug screenings before the next debate.
"Athletes, they make them take a drug test. I think we should take a drug test prior to the debate," Trump said. "I'm willing to do it."
Trump lays out drug policy
Trump's comments about Clinton came as he laid out his policy to combat drug abuse and trafficking while speaking in New Hampshire, a state that has become a flashpoint of opioid and heroin abuse.
The Republican nominee called on the Federal Drug Administration to sped up its approval of "abuse-deterring drugs," called for lifting the cap on the number of patients doctors can treat and said the federal government should reduce the amount of opioids that can be manufactured in the US.
Trump also said he would seek to further incentivize state and local governments to mandate treatment through drug courts to help drug offenders break their addictions, and said he supported giving first responders' access to the drug Narcan, an antidote that can save the lives of individuals who overdose on opioids.