Lovely old porcelain mug, 3 3/4" high. Mugs of this shape are often called "shaving mugs", but many were made and used for for drinking. There is nothing masculine about this mug - softly colored butterflies and a pale pink rim make it suitable for a woman or child.
The mug is in excellent condition, with some wear and stain on the base. It is unmarked, but most likely made in Germany circa 1900.