Tonic is much more than a bit player in a G&T. A lot of it’s good enough to drink solo Tonic is much more than a bit player in a G&T. A lot of it’s good enough to drink solo The Guardian’s journalism is independent. We will earn a commission if you buy something through an affiliate link. Learn more . The Guardian’s journalism is independent. We will earn a commission if you buy something through an affiliate link. Learn more . I f a tonic is something that “makes you feel stronger and happier”,