
lemeres |

Ignoring spells, an alchemist has two different discoveries related to fast healing. Spontaneous healing gives you a round of fast healing 5/2 levels, while healing touch doubles that to 5/level (it has other stuff about sharing this healing with others....but why waste those precious precious hechpeeessssss)
Since it takes no action to activate, and activates automatically if you fall unconscious from going below 0 hp, it is basically like having more hp per level (with the added benefit of taking out bleeding effects if I remember correctly). Between that, their mutagen, a few tricks to get better armor, and maybe a half decent weapon, and you can specialize your alchemist to be a rather good melee combatant in a style like a barbarian.

Umbranus |

An alchemist with a one level dip into life oracle can get fast healing.
This is how it works: He needs to take the tumor familiar discovery because the tumor familiar gets fast healing while merged with the alchemist. Now if the alchemist dips into life oracle and takes the life link revelation a part of his damage is transferred to his familiar. That way both heal. The alchemist throuch life link and the familiar through his fast healing.