This word is from the Spanish tónico.
Ang toniko ay banayad na gamot na pampasigla sa katawan. Ang tonikong tubig ay inumin na nilagyan ng quinine, na noong nakaraang siglo ay ginagamit na panlaban sa malaria.
A tonic is a medicinal substance taken to give one a feeling of vigor or well-being. Tonic water is a carbonated drink in which quinine is dissolved. It was originally used to help one avoid getting malaria.