I highly doubt the possibility of erasing one's memory with intent. There's no proof of any scientific process that can wipe clean or temper with a person's memory, none that I've seen or come across. It is probably one of the many major strives yet to be achieved by man.
However, a person's memory can actually be erased or tempered with, through unintentional means. Let's not get it wrong. These are two different cases. The earlier is a process which can be induced on demand, while the later is mostly caused by accident or as result of a persons's deteriorating health system, which results to either short or long-term loss.
People who suffer from dementia, Bipolar disorder, schizophrenia and Alzheimers are said to have and experience different levels of memory loss. These are instances of health related memory loss. An example of accidental memory loss might be someone who slipped into a coma, wakes up and doesn't remember much.
I wouldn't rule out the possibility of induced memory loss, I think it's under way like @keibah pointed out...or maybe it already has but we're unaware of it.