Willie Nelson has given up smoking weed after recent health issues ... but he still gets high.

The 86-year-old recently explained, "I have abused my lungs quite a bit in the past, so breathing is a little more difficult these days and I have to be careful."

Willie added, "I don't smoke anymore, take better care of myself."

A source says it's true, he's not smoking weed.  However, he still vapes and eats cannabis-infused items.  

Willie's grown a weed empire over the course of his career -- even launching Willie's Reserve -- a cannabis company selling everything from joints to weed-infused candy and vape products.