As a Navy SEAL and then a professional wrestler, Jesse Ventura has developed a reputation as a fighter. Now he's taking on a new battle, the U.S.'s "War on Drugs" that has sought to outlaw illegal substance abuse, but led to a number of spillover effects.

In his new book, "Jesse Ventura's Marijuana Manifesto", the former Governor of Minnesota argues for the legalization of pot. He makes no distinction, however, between medical and recreational.

"I'm in favor of all. There is no difference. The entire plant is a medical plant," Ventura told CNBC's On the Money in an interview.

He said he took on the cause for a personal reason. "Someone very, very close to me developed…epileptic seizures and was seizing four times a week," said the former governor.

Ventura said the person, who he declined to name for privacy reasons, took four types of pharmaceutical medicines. "None of them worked. They all had horrible side effects," he added.

"Finally in desperation," Ventura took the person to Colorado, where weed has been legalized. After taking medical marijuana the person has been "completely seizure-free and is completely off all of the pharmaceutical medicine," for at least two years. "So marijuana cured the seizures," he added.

Including Colorado, at least 25 states and the District of Columbia have legalized some form of marijuana for either medical or recreational use, or both.

Contrary to what some skeptics say, however, Ventura argued the legalization movement has had a virtuous effect. "In every state that's legalized marijuana, heroin use has gone down. The exact opposite of the propaganda they've been pumping into us for years."

Meanwhile, the movement has boosted state coffers somewhat. The Colorado Department of Revenue has seen tax revenue on marijuana sales increase from $56 million in 2014 to $113 million last year, to an estimated $140 million this year.

Ventura added that the Rocky Mountain state now has millions more "to spend on schools and on infrastructure and all that."

At one point, Ventura was mooted as a potential independent presidential candidate. He told CNBC there was no love lost for either Donald Trump or Hillary Clinton, both of whom have struggled under the weight of being polarizing.

"I would love to see Hillary and Donald both lose. You have two candidates here where their negatives are record high," Ventura said. They're both hated by the majority of the people. Well, vote for someone," Ventura tells CNBC.

The former Minnesota governor is supporting Gary Johnson, the Libertarian former New Mexico governor, for president.

"I'm for Governor Johnson for two reasons," Ventura said, citing armed conflict abroad and drugs. "I want out of the wars in the Middle East. Gary Johnson said he'll do that. I want an end to 'the war on drugs.'"

He did express some surprise at Trump success, who he said has "rattled his sword for years. I was surprised he finally did it." In 1998, Trump backed Ventura's independent bid for governor.

"My disappointment was he did it as a Republican. That's why I can't support him and won't support him," Ventura added.

"I don't support Democrats and Republicans because they've been in charge for 150 years and look at the mess we're in."

On the Money airs on CNBC Saturday at 5:30 am ET, or check listings for air times in local markets.