The father of Anna Nicole Smith's daughter told a court that the ex-Playmate "took more medications than I've ever seen anyone take" and complained to a doctor now charged with conspiring to provide her with controlled substances.

But Larry Birkhead later acknowledged the celebrity model had an array of ailments, ranging from back pain to seizures, and each one required specific medication.

At a Los Angeles hearing, a defence lawyer led him through descriptions of the illnesses to suggest Smith was being properly medicated by her doctors. "I was concerned that Anna was taking too many medications," said Birkhead, a photographer who moved in with Smith in 2004.

Birkhead said he raised the drug issue during a visit to Dr Sandeep Kapoor in mid-2005 about a minor ailment. Kapoor was Smith's doctor at the time. "At the end of the visit, I said to him she might be taking medicine from someone else in addition to him," Birkhead said.

"What did Dr Kapoor say?" prosecutor Renee Rose asked.

"He said, 'I believe we have that under control now', and that's all that he said," Birkhead replied.

Kapoor, Howard Stern, Smith's boyfriend-lawyer, and Dr Khristine Eroshevich are charged with conspiring to illegally provide controlled substances to Smith. All three have pleaded not guilty.

The defendants are not charged with Smith's death in February 2007, which was ruled an accidental overdose.

Birkhead took the stand at a preliminary hearing to determine if the defendants should stand trial.

After Smith died, Birkhead waged a paternity battle with Stern, who claimed he had fathered the model's daughter, Dannielynn. Birkhead won after producing DNA proof that he was the father.