Her relationship may be on the mend, but Brooke Mueller still has many personal issues to sort through.

Sources tell TMZ that Charlie Sheen's wife is in rehab for substance abuse, as she reportedly checked into The Canyon rehab facility in Malibu last Tuesday.

Similar reports sprung up late last month, but Mueller's mother and lawyer insisted she was in a facility to treat an infection she developed following wisdom tooth surgery.

If this news is valid, it wouldn't come as a shock: Brooke was arrested 1996 for drunk driving, and in 2001 for cocaine possession.

She also had a .13 blood-alcohol level at the scene of the alleged Christmas Day incident between her and Sheen, where the latter stands accused of threatening his wife with a knife.

We wish Mueller a speedy recovery.