Dangerous dieting is as old as Hollywood.

And it can be deadly.

Singer Karen Carpenter died at 32 of complications from anorexia nervosa, specifically "cardiotoxicity" brought on by the chemical emetine, found in the now banned over-the-counter drug, ipecac.

Glamazon Anna Nicole-Smith, who had gone through years of yo-yo dieting, was on a host of prescription medications, including two that could be used for weight loss, when she died of an accidental overdose at the age of 39.

Screen legend Judy Garland was hounded by film executives who told her she was too fat. The actress turned to pounding pound-shedding amphetamines over the course of her lifetime. She died at age 47 of a barbiturate overdose.

Now experts say destructive dieting only getting worse.

“It is such an image-conscious industry. I find more and more women and men are utilizing whatever they can do to try and stay thin. People are looking for a quick and easy way to cheat,” Dr. Reef Karim, director of The Control Center and assistant clinical professor at the UCLA Semel Institute for Neuroscience, told FOX411’s Pop Tarts. “Their livelihood, their ability to be cast in a role, their entire way of making money is completely dependent on staying thin.”

Reef, who has treated several celebrities, says cocaine and crystal meth are both high on the list of preferred appetite suppressants. One recent patient who constantly felt lethargic and couldn’t lose weight turned to meth snorting.

“In the short term, she said she actually felt okay and she actually felt like not eating, but in the long term, she got psychotic. That’s when she came to my office, because she was paranoid and she thought the police were after her and the CIA had bugged her apartment, and all sorts of other stuff," Karim said. "In the end, she had to be treated for a meth problem, and it all started 100 percent, because she wanted to lose weight.”

Reef said the side effects of a "meth diet" are chilling. “It’s a strong appetite suppressant, but it will also fry your brain. It’s neuro-toxic and it’s going to kill some of your nerve terminals," Reef said. "You’re going to get 'meth mouth' and all sorts of other craziness is going to happen to you all for the sake of shedding a few pounds."

("Meth mouth" is a term for advanced oral decay commonly found in meth abusers.)

But dangerous diet aids need not be illegal. Dr. David Sack, CEO of Malibu’s celebrity-saturated rehabilitation clinic Promises, says stars routinely seek out and get addicted to prescription medications to pop the pounds. These drugs include:

-- Psychostimulants designed to decrease appetite

-- Hormones such as thyroid hormone to boost one’s metabolism

-- The male hormone androgen to increase muscle mass

-- Fat blockers to attempt to stop fat being absorbed in the gut

-- Diuretics to increase the amount of water released from the body

-- Depression medications containing serotonin to diminish one’s desire to eat

Sack said one of the most popular drugs misused for weight loss in the entertainment industry is Adderall, which is correctly prescribed to those diagnosed with with Attention Deficit Disorder (ADD) or Attention Deficit Hyperactivity Disorder (ADHD.) The drug gained extra attention last year when doctors at the UCLA rehab facility, who were treating Lindsay Lohan, told TMZ that the actress had been misdiagnosed with ADD, and the consequent use of Adderall to treat the phantom affliction may have been what caused her to become unhinged.

And there are more drugs on the way, Sack says.

“Recently ... a drug that blocks central cannibinoid receptors, based on the observation that marijuana and related chemicals stimulant appetite, has been studied for weight loss, but its not approved in the U.S,” Sack said.

So how does a celebrity get a prescription for a drug they want to use to lose weight?

“Overseas medications provide a pathway for people who cannot afford legitimate medical prescriptions,” Sack said. “The rules regarding the import of drugs by individuals from pharmacies have slackened are not closely enforced.”

And when you have a little star power, getting drugs gets even easier.

“I cannot even tell you how many younger women take Adderall. It is all over the place. How many of them have ADHD that is truly diagnosable? Very few,” Reef said. “Some people get them from friends that truly have ADHD. Those friends ask for more medication than they really need and give it to their friends. Then there are those people that try to fake that they have ADHD and fake all sorts of symptoms to get the medication, hoping that they lose weight.”

A rep for Teva Pharmaceuticals, maker of Adderall IR, notes that "Adderall is a Schedule II controlled substance, and the package insert clearly states the risks associated with incorrect dosage, misuse or abuse and recommends that doctors properly monitor patients. This medicine is not recommended for patients with a history of drug abuse. Adderall is one of many prescription drugs subject to abuse. Such actions can have unfortunate consequences." A rep for Shire pharmaceuticals, maker of Adderall XR added that the company "supports the appropriate use of its medications approved for the treatment of ADHD and does not support abuse, misuse, diversion, or unapproved indication of these medicines."

A few years ago Clenbuterol (nicknamed “clen” and “the size zero drug”) hit the Hollywood scene. Legal only for use in horses as an effective equine asthma treatment, clenbuterol is a potentially life-threatening substance that was initially discovered by bodybuilders as a means of burning fat while building muscle mass. Nonetheless, it was hailed as a Hollywood and fashion industry wonder drug, and one which was easy to find on the Web.

And as if the drugs weren't dangerous enough by themselves, eating disorders and co-addictions often accompany their misuse.

“The anorexics, the bulimics, the binge eaters are coming in, usually with alcohol addiction and prescription drug addiction," said Dr. Gregg Jantz, eating disorder specialist and founder of The Center in Washington, DC. "The average client that we see comes in with six or seven medications that they are currently using. A lot of times, they’re taking something for depression, and they’re taking something for anxiety. The problem is that they’re mixing their medications."

So is there any hope for desperate actors and actresses in a town built on svelte good looks?

“The more problematic behaviors we have in regards to body image, the more people are going to cut corners and find impulsive ways to get there,” Reef added. “A lot of that is going to be pills and drugs, and anything one can do to curb their appetite and look thinner. They start out thinking ‘this is a good idea,’ but end up in my office.”

Or worse.