The presenter, who is completing the sponsored walk for Breast Cancer Care, found the illegal substance when walking the Inca Trail earlier this week.
She told The Sun: "It was a shedload of coke and the whole thing seems utterly unreal now.
"Initially, I couldn't quite believe what I was seeing and wasn't too sure quite what to do with it. I had visions of me being framed by police clutching the stuff."
Local authorities were contacted and came to collect the drugs.
Other celebrities participating in the trek include Fearne Cotton, Alexandra Burke, Gabriella Cilmi and Amanda Byram, alongside six women who have been diagnosed with breast cancer.