Cassie in The Wotch tried this, with the predictable results - instead of getting Robin's affections, she instead gained the unwanted attention of his kid brother and a guy at school whom she disliked. Naturally enough, it is only after she fails at this that he asks her on a date for completely unrelated reasons, causing her to pour the rest of the vial in a decorative plant at the local mall—which alsofalls in love with her.
In Charby the Vampirate Mye cooked up a number of love potions for Victor as well as shapeshifting to look like an attractive adult woman while she was stalking him.
In Clan of the Cats, Lesbian Vampire Rose uses an anti-love potion to cause Chelsea and Jubal to break up, so she could then seduce Chelsea. This actually works, as she leads Chelsea on a minor rampage through New Orleans, but after Chelsea has a My God, What Have I Done? moment, the truth comes out about what Rose had done to them.
In the Spells R Us comic "Dream Girl", the wizard sells a love potion to a girl, but there's a catch. When the girl tricks the boy she likes into drinking the potion, it has no effect on him. Instead, it turns her into his ideal woman by changing her mind and body. And the effects are retroactive, which means that even her parents have no memory of who she used to be.
Sluggy Freelance: The Love Potion: PART 1 and PART 2. Although this is where the subject comes up. Gwynn tries to use this love-first-person-you-see potion to make Riff fall in love with her, Dex fall in love with Zoë, and Torg fall for... er... Bun-bun. Zoë initially protests, but quickly comes around as her one-sided crush Dex drinks it and immediately starts reciprocating. Of course, such a premise cannot be played without the pitfalls: Bun-bun falls for Gwynn, Riff falls for Crystal, and Crystal falls for Torg. Also, the potion was supposed to wear off gradually, so it would basically just keep the romance going long enough for genuine love to develop, but because the potion was mixed with alcohol, and/or because the person giving the recipe had his own agenda, the effects actually got stronger over time and included a tendency to go Axe-Crazy, making it a Love Dodecahedron with a generous dose of Murder the Hypotenuse.
"I love Zoe so much! I can hardly contain myself! I love her enough to die for her! I love her enough... to kill!" ... "KILL KILL MURDER KILL STABBITY STAB STAB STAB KILL"
Parodied rather amusingly in a Death Note fan comic. Even Halle points out how "stupid and overused [an] idea it is," though her Common Sense is quickly shoved to the side. If only Near had listened, his face might not have been so humourous when things didn't go exactly as planned.
Nodwick's Garage Sale story arc featured a would-be Casanova slipping a love potion of the "First person you see" variety into Piffany's lemonade. Needless to say, Hilarity Ensues.
In one Oglafstrip (Warning: SFW), a man drinks a love potion that was supposed to be given to the woman that he wanted to fall in love with him, and he falls in love with the potion.
In Think Before You Think, it is revealed that Mandi desperately wants a lesbian love potion, but no one finds out why until a while later. This leads to a series of somewhat weird events.
It more-or-less works in Yang Child, where a Mysterious Watcher slips a love potion to the heroes in order to inconvenience them. It ends up on the "wrong" target and is used way after B.B. date.
Discussed in Erfworld. The main protagonist is stuck in a situation where he would consider pursuing any of his possible romantic partners as effectively rape (although due to cultural differences they wouldn't). The exception is one woman who is already in love with him, but who's feelings he doesn't reciprocate. In a discussion with a magic user that has relationship magic among her disciplines he suggests resolving this by taking such a potion himself so that he'd return her affections; she's disgusted by the idea for the same reasons he doesn't want to pursue his followers, and explains that while potions for related purposes "can be quite fun" nothing like what he's describing exists.