Howard Lotsof was 19, addicted to heroin and searching for a new high in 1962 when he swallowed a bitter-tasting white powder taken from an exotic West African shrub.

“The next thing I knew,” he told The New York Times in 1994, “I was straight.”

The substance was ibogaine, an extract of Tabernanthe iboga, a perennial rain-forest plant found primarily in Gabon. By Lotsof’s account, when he and six friends who were also addicted tried ibogaine, five of them immediately quit, saying their desire for heroin had been extinguished.

It was the start of a lifelong campaign for Lotsof. And now thousands of former addicts around the world and some scientists contend that ibogaine should be tested for its ability to halt heroin and cocaine cravings and end addiction. Ibogaine is used in many countries, but is banned in the United States.

Lotsof, who was 66, died Jan. 31 at a hospital near his home on Staten Island, N.Y. The cause was liver cancer, his wife, Norma said.

“His great achievement,” said Kenneth Alper, an associate professor of psychiatry and neurology at the New York University School of Medicine, “was in inducing the National Institute on Drug Abuse to undertake a research project on ibogaine that produced scores of peer-reviewed publications and paved the way for FDA approval of a clinical trial.”

The Food and Drug Administration did approve the trial, Alper said, but it was never completed because of contractual disputes and lack of financing. Ibogaine remains banned by the federal government.

Scientifically controlled testing is needed, Alper said.