Malathion is an organophosphate compound. You may hear that they affect the same group of receptors as some of the potent nerve gases like sarin or VX; however, those agents are neuro-selective (i.e. causing paralysis) and malathion is not. Organophosphates produce other effects--most notably increased lacrimation (tearing), salivation, increased bronchial secretions. It is this latter that is the most fatal; however keep in mind that a little malathion won't kill anyone. I myself have bitten into a tomato in the past that was heavily laced with malathion, thanks to some idiot local farm that must have harvested too soon after spraying. I was salivating like pavlov's dogs, but it would have taken a lot more exposure to cause serious problems.
That said, I would *not* use malathion in the home. It stinks to high hell and its effects are not appropriate for home use, if you ask me. Wear gloves and some type of face protection when spraying outdoors and you shouldn't have any problems. I'd air the plants out for at least a day or two before bringing inside.