"(I Don't Know Why) But I Do" is an R&B song written by Paul Gayten and Bobby Charles (as Robert Guidry), and performed by Clarence "Frogman" Henry.

It was Henry's biggest U.S. hit, reaching No.

The B-side on the single release was "Just My Baby and Me".

The UK version spent 19 weeks in the charts and peaked at No.

[3] The song was made popular again after its use in a 1993 UK television commercial for the Fiat Cinquecento,[4] appearances in the 1994 film Forrest Gump, the 1999 film Mickey Blue Eyes, and a 2019 commercial for Expedia and its ability to provide dog-friendly hotel accommodations.