"Doctors do not have a license to pump innocent and often vulnerable people full of dangerous chemicals," Brown told a news conference. "Somebody died here, and this is bad business."
In addition to conspiracy, the charges filed Thursday include unlawfully prescribing a controlled substance and prescribing, administering or dispensing a controlled substance to an addict. Stern faces six felony counts and the doctors face seven each.
Each defendant faces up to five years, eight months in prison, district attorney spokeswoman Sandi Gibbons said.
"Howard K. Stern is the principal enabler, and Dr. Eroshevich and Dr. Kapoor are prescribing drugs excessively to a known addict and using false and fictitious names, all in violation of the law," Brown said.
Medical Board of California spokeswoman Candis Cohen said action would be taken against the two doctors' medical licenses after the criminal proceedings had been resolved. A range of disciplinary action could be taken, depending on the evidence, including possible revocation of their licenses.
Smith's life had become a tabloid fixture by the time she died Feb. 8, 2007, in Florida. Embroiled in a battle to inherit millions of dollars from her late billionaire husband's estate, her own son had died shortly after she gave birth to a girl.
Asked what may have been the motive for the alleged conspiracy, Brown suggested the potent allure of wealth and glamour.
"There's a certain psychic gain here, part of the glitz and the celebrity and the power. There's a lot of money floating around," he said. "Is it self-indulgence? Is it some power trip? Is it just getting some contact high off of celebrity? That remains to be seen."
Stern and Kapoor turned themselves in Thursday night and each posted $20,000 bond. Eroshevich was expected to surrender Monday.
Her attorney, Adam Braun, acknowledged Eroshevich wrote some of the prescriptions using fictitious names for Smith, but asserted it was for privacy reasons and not intended to commit fraud.
Braun said Eroshevich began treating Smith in September 2006 when she suffered a nervous breakdown stemming from the death of her 20-year-old son, Daniel Smith, from an accidental drug overdose three days after his mother gave birth to a girl.
Brown declined to comment when asked if there was a trail leading to Daniel Smith from doctors in California, nor did he comment on whether other individuals may face charges.
"We have given you the evidence that we think is ready for the prosecution," he said.
Eroshevich, who was Smith's psychiatrist, traveled several times over six months to the Bahamas, where Smith was living with Stern and wrote the prescriptions.
The criminal complaint also alleges Kapoor gave her excessive amounts of sleep aids, opiates, muscle relaxants and methadone-like drugs used to treat addiction, knowing she was an addict. Kapoor saw Smith in the spring of 2006 when she was treated at a Los Angeles County hospital for opiate withdrawal and prenatal care for the pregnancy of her daughter Dannielynn, according to the complaint.
Stern's attorney L. Lin Wood said he anticipated releasing a statement about the case sometime Friday.
Kapoor's attorney, Ellyn Garofalo, said the charges were without merit.
"I was surprised that after all this time, these charges surfaced suddenly like they did," she said. "They are attempting to impose criminal penalties against a doctor who acted in good faith and provided the best medical care he was able to under the circumstances. If not for the fact this was Anna Nicole, I don't think these changes would have been filed."