Larry Birkhead -- Do You Swear to Tell the Truth ... ?

8/20/2010 1:30 PM PDT BY TMZ STAFF
Larry Birkhead returned to an L.A. County Superior courtroom this morning to continue spilling his guts about Anna Nicole Smith's prescription drug use.

On Thursday, Birkhead testified that he saw Smith take numerous prescription drugs -- but claims that Anna had told him that she wasn't an addict. Birkhead also told the court that Anna insisted she had a high tolerance for certain meds.

Howard K. Stern, Dr. Khristine Eroshevich and Dr. Sandeep Kapoor are all facing charges of conspiring to unlawfully provide drugs to Anna Nicole. They have each pled not guilty.