This spell applies to all two-legged, generally mammalian figures near to or less than man-size, excluding all monsters in the "Undead" class but including Sprites, Pixies, Nixies, Kobolds, Goblins, Orcs, Hobgoblins and Gnolls. If the spell is successful it will cause the charmed entity to come completely under the influence of the Magic-User until such a time as the "charm" is dispelled (Dispel Magic). Range: 12"
In OD&D there was no limitation as to what the MU could make his victim do. He could force him to commit suicide, or commit acts against his alignment. This situation remained unchanged in Holmes, where the only changes have to do with the duration. It is not until the PHB and Moldvay that there are restrictions (suicide and alignment) on what the MU can force his victim to do. While, as Alexis points out, the debate around Charm Person tends to center on if it would be too powerful to allow suicide, I cannot help but wonder if the real reason that these changes were made involved PR instead of play balance.
In the '70s and early '80s the American public became very concerned about cults. There was a decade of incidents bookended by the Manson Family and Jonestown involving charismatic leaders convincing their followers to do horrible things. Jonestown was in November and the PHB was in June (I think) of 1978 so obviously that event had not happened yet, but the issue had been growing in the American consciousness since the late '60s. While not strictly a cult, the bizarre events surrounding the Patty Hearst kidnapping have a Charm Person feel to them.
While there is no doubt that the debate around Charm Person has mainly been about power level, I wonder if the initial reason for the change had more to do with distancing themselves from cult incidents in the news. This is all speculation on my part, and may be groundless.