The phone call that Barbara Eden had dreaded for years came at 3 a.m. last June 26: Her only child, Matthew Ansara, was dead of a heroin overdose. Six hours earlier, police had found Ansara, a 35-year-old actor and amateur bodybuilder, slumped over the steering wheel of his truck at a gas station in Monrovia, Calif. At the time of his death, he was playing the part of an inmate in the upcoming prison thriller Con Games. "He won a lot of battles," says Eden, 67. "But he lost his personal war."

Until recently, Eden hesitated to discuss the tragedy. Now, however, she is using her star power to help other parents recognize the signs of drug abuse. "I'm telling them, 'talk to someone who has been through this, and seek help for your child right away,'" she says. "If you treat this disease early, you can stop it."

Matthew was born to Eden and actor Michael Ansara (known for his lead role in the '60s TV series Broken Arrow,) in 1965, the same year his mother shimmied to fame as the mischievous genie on I Dream of Jeannie. The couple's 15-year marriage ended in 1973, when Matthew was 9, a blow that she believes helped turn him toward drugs. Eden wed Chicago newspaper executive Charles Fegert in 1977, but split with him six years later. In 1991 she married real estate exec Jon Eicholtz. "Jon is bright, funny, nonjudgmental," says Eden. "He's my oak." At their Beverly Hills home, she spoke with correspondent Frank Swertlow about her son's life and death.

I first knew Matthew was in trouble in 1984, when he was 19. He had chosen to live with his father after I remarried, but came back to live with me when my second husband and I divorced. He'd flunked out after one semester at the University of California at Santa Barbara and was supposed to be commuting to Valley College. I noticed that he slept a lot. Then, one day after he'd left for school, I saw that he'd forgotten his books. I raced out to the college and walked all over that campus looking for him. Finally I went to the registrar's office and found out he wasn't even registered.

When I confronted him at home, he got angry, threw things and stomped out. That night he still hadn't come back, so I called his father. We searched for him everywhere, even under freeways. For months we had no idea where he was. Then a friend of Matthew's, who took him in, told us he'd spent most of that time living on the streets.

Matthew never told Mike and me that he was using heroin—he didn't want to hurt us. But we figured it out because he had been acting sluggish, losing weight, staying out all night. I insisted that he enter a rehab center, and I let him come back home when he came out a month later. But he started using again. The professionals told us that if your child is using drugs he has become the drug: He is no longer your child, and he no longer has a home with you. So I locked him out when he was 20, which was the hardest thing I ever had to do.

He was in and out of rehab for the next 14 years. And even though Mike and I had been divorced for ages, we went through a lot of it together with him. We saw doctors and counselors and attended Al-Anon meetings. We got a crash course in drug abuse.

One thing we learned was that Matthew had started using drugs when he was only 10. We were living in the San Fernando Valley then, and I had no idea that one of our neighbors was growing pot and smoking it with the kids in the neighborhood. They were hippies with money who probably thought what they were doing was cool. For what they did, I'd happily kill them.

I think marijuana can be extremely addictive, especially if the child starts smoking early and has a genetic predisposition to addiction. It puts him on track to use more powerful drugs to avoid facing life. Mike and I had alcoholism in our families—his grandfather, my aunt and uncle. Still, that didn't make us more alert to Matthew's early drug use. And by the time we found out, it was too late to save him.

When Matthew was in his 20s he started stealing from us—silverware, money from my husband Jon's wallet. When he visited us, sometimes he'd laugh and say, "Here I am, better lock up everything." But when he was sober, he'd tell us, "I'm so sorry. I love you more than anyone in the world."

He had some hopeful times, but they didn't last. At 27 he fell in love with a wonderful woman, an accountant, and they had a big, fancy wedding in Oregon. For a year he did well. He had a job and studied creative writing at UCLA.

Then the cycle began again, and he went back on heroin. His wife left him—wisely. He blamed her, which isn't surprising: A drug addict never takes responsibility for his own actions. One day, soon after they separated, he called me, sounding half dead, and said, "Mom, I'm sick." Mike's wife and another friend drove with me to a bad part of Venice, Calif., and we found him in his apartment, unconscious from an overdose. He weighed 200 lbs., but we three women got him up and to the car and took him to the hospital, which saved his life. I was so mad at everything and everyone: Here I was paying the rent, and his apartment was filthy—no sheets on the bed, cartons of takeout food piled in the sink. And he was hooked again.

At 29 he was diagnosed with clinical depression and given medication. It didn't help. He couldn't keep a job, couldn't stay in school. Although he went public with his addiction in October 1999, when he was interviewed for a documentary on me, that didn't mean he was ready to quit.

But in the last year of his life, he got clean again—and he really seemed to be getting it together. He was about to be married to a wonderful girl and was acting in movies. He was so proud of getting jobs based on his talent; he never told anyone who his parents were. He'd visit me and Jon several times a week. One day he told me, "Life is great, Mom. I can't believe I spent so many years not being awake to how green the trees are."

Then he was dead. He had shot up with a dose of unusually pure heroin, and it was too much for his heart. And I had another shock: Along with a syringe, the police found vials of anabolic steroids in his truck. To bulk up for bodybuilding competitions, he had been injecting himself with this dangerous drug. Even when he was getting in shape, he did it like an addict—obsessively. He was unable to do anything in moderation.

I'm still trying to figure out why Matthew turned to drugs. Show business takes a lot out of a family, but I chose to work on sitcoms so I could be home at night. Sometimes I blame the divorce. Matthew took it horribly. He wanted his mommy and daddy to stay together. If I had to do it over, I would have waited until he was older. But then I remind myself that so many kids from divorced homes don't become addicts.

I don't have any answers. All I know is that I will always miss my sweet son.