Professor Wasp's Meddling Tonic increases the MEDDLING LEVEL of whoever drinks it. According to the label, it also alleviates Anemia, Depression, Brain-Fag, Sleeplessness, Physical & Mental Prostration, Nerve Troubles, and (in)Convalescence. Professor Wasp's Meddling Tonic is also recommended by over 10,000 doctors.
Professor Wasp uses this to meddle in a lot of canonical events in a donation funded non-canon sequence, somehow causing even more confusion as to how things really happened or not. He then meddles with Death, altering his appearance and giving him yet another Ace Dick instead of a Tome of Wayfaring Souls.
The tonic only has appeared due to Professor Wasp, and since Professor Wasp is a donation funded character, it's safe to say that the Tonic is non-canon.