Pot stocks were trading lower Friday ahead of a key Food and Drug Administration hearing on the efficacy of food products infused with cannabidiol, the non-THC active ingredient in cannabis. 

The public hearing is intended to obtain scientific data and information about the cannabis-derived product. 

The FDA will webcast the public hearing here. The event will feature opening remarks from Ned Sharpless, the acting FDA commissioner, oral comments and formal presentations from professors.

Shares of Tilray (TLRY) - Get Report  were down 2.28% to $38.23 in trading Friday.

Aurora Cannabis (ACB) - Get Report  was falling 3.5% to $7.72.

Canopy Growth (CGC) - Get Report  tumbled 3.3% to $40.79.

Cronos (CRON) - Get Report  fell 0.34% to $14.85.

WatchOne Thing Investors Need to Know Before Investing in Cannabis