http://en.wikipedia.org/wiki/Lye and highly alkaline. Healthy skin pH is 4-5.5 on average, nor do bacteria like acidic environments.
Wikipedia says this:
A lye is a liquid obtained by leaching ashes (containing largely potassium carbonate or "potash"), or a strong alkali which is highly soluble in water producing caustic basic solutions. "Lye" is commonly the alternative name of sodium hydroxide (NaOH) or historically potassium hydroxide(KOH).
Some of the products containing Sodium Hydroxide include:
Murad Advanced Active Radiance, SkinCeuticals A.G.E. Eye Complex, VERSO Day Cream, Caudalie Anti-Wrinkle Defense Serum & Cru, Caudalie Premier The Eye Cream, Proactiv Complexion Perfecting Hydrator, Algenist Anti-Aging Eye & Genius Cream, and Clarisonic Opal Anti-Aging Sea Serum, Epionce Melanocyte Pigment Perfecting Serum, and Epionce Facial Lotion.