The issue of what players take to get to sleep has become a discussion point after Glen Johnson revealed some players had taken Pro Plus tablets on Tuesday ahead of England's World Cup qualifier with Poland in Warsaw.
"I think some players do take sleeping tablets at night," said Ferguson. "I don't know which ones. There are all different types and some very mild ones. I leave it to the doctor."
Another England player admitted some then took sleeping pills to counter-attack the effect and allow them to get to sleep following the postponement.
Both Phil Neville and Rio Ferdinand went on Twitter to confirm it was nothing new and that neither sleeping pills nor caffeine tablets, which it has also been suggested were taken by Roy Hodgson's men, had an adverse effect on player performance.
Ferguson clearly does not believe it is an issue, judging by the jovial way he responded to a further query about whether his players take caffeine tablets.
"I don't think so," he said. "It's me that's needing them.
"I wish I had taken a sleeping tablet before this press conference. It would have made it a bit easier."
Source: PA
Source: PA