Just like everything else, there are a lot of myths surrounding Reiki or do's and don'ts. You can't do Reiki on someone with Diabetes, has a Pacemaker, is schizophrenic or has seizure disorder. Well I've worked on 'em all, no problem! But just the other day I heard about a new one - the 21 day self-treating rule.
The attunement (sacred ceremony that a certified Reiki Master Teacher performs on you that connects you to the Reiki energy so that you can channel it for yourself), elicits a 21 day cleanse or detox in the body. This cleanse clears out any old negative, stuck energy in your energy field or body for the purpose of making you a clearer channel for the energy, in essence.
We instruct all of our students to began performing daily whole body self-treatments with their now "Reiki hands" as soon as they become Reiki. Some teachers are telling their students that you only have to do this during the 21 day cleanse/detox, hence the confusion possible. NOT SO! A Reiki practitioner is expected to perform this daily ritual for themselves EVERY SINGLE DAY for ever, especially if they are doing a lot of Reiki on others or sending a lot of Distant Reiki Healing to others, or going through a particularly rough cleanse (that's pretty rare).
I think this myth about only doing a daily self-treatment for the 21 days you are going through your cleanse has more to do with our crazy western lifestyle (on the go all the time, little time for self) so when you tell someone they have to perform this ritual on themselves (a one hour or more process) every day they freak out. So maybe some teachers thought they might be able to convince more of their students of the necessity of doing it if they shortened it. (Just a thought - I know lot of my students do!). Others think it got confused with the 21 day cleanse/detox.
Doing a daily Reiki self-treatment removes negative energy from your energy field and recharges your body, as well as opens, clears and balances your chakras and much more. So you can see it is very beneficial and of course, if you are having some kind of issue other than just your daily stuff (a cold, flu, allergies, injuries, surgeries, major stress,etc.) it will help you recover faster and maybe get sick less often.
The problem with Reiki and myths is twofold. We bombed the holy H word out of Japan in WW II and a lot of records were destroyed that possible could have given us a better picture about it's origins and history and it's founder Dr. Mikao Usui. The memorial society that some say was formed after Dr. Usui's passing (the Usui Reiki Royho Gakkai), is a very secret and secretive society. Reiki had to go underground after the war as the United States forbid anyone in Japan from practicing it. The Gakkai is still in existence today and they teach and do Reiki exactly as Dr. Usui instructed them to over 100 years ago. It is a closed society and not really interested in sharing it's secrets with us. Can't say as I blame them.
We have made contact with one of it's President's and one of it's members defected in a sense and has shared information with us, and more and more information is being uncovered about Reiki, thanks to the efforts of people like Reiki Master Teacher and author of many books on Reiki "Frank Arjava Petter, and many others.
It is very unlikely that we will ever know the complete history of Reiki and all there is to know about it and it's founder, so we just have to trust that it works and not get too hung up in the whys and wherefores, and try to clear these myths as they come up.