Doctors are being told to adopt a new policy of writing letters that are easier for patients to understand.
The Academy of Medical Royal Colleges says too often correspondence contains complex medical jargon rather than plain and simple English.
Using the phrase "twice daily" to explain the dosing of a medicine is better than the Latin abbreviation "bd", for example.
Patients should ask their local hospital to comply, the academy says.
The Please Write to Me initiative is aimed mainly at doctors working in outpatient clinics, although it is best practice for all clinicians who need to write clinical letters.
Doctors are being asked to write directly to patients, rather than sending them a copy of a letter penned to their GP.
The academy says this should help avoid blunders or offence caused by writing about patients in the third person.
It cites the example of a surgeon branded sexist after praising a father for "manfully stepping in" to take his daughter to a hospital appointment when his wife was too ill.
Another consideration is the tone of the letter. A familiar style, such as: "It was a pleasure to meet you and your husband for the first time," might sometimes be appropriate – but at other times a more distant or formal style might be appreciated, say the guidelines.
Doctors are asked to avoid potentially stigmatising words: "'You have diabetes,' is better than 'You are diabetic.'"
They should think about softening the impact of potentially sensitive information by using a more non-committal style, as with: "During the examination, the tremor and stiffness in your right arm suggest that you have Parkinson's disease."
And any medical words should be translated in plain English. For example:
Hospital doctors should also consider telephoning the patients rather than breaking bad news in the letter if test results are potentially upsetting, the academy says.
The initiative is being led by Dr Hugh Rayner, a kidney specialist, who first started writing directly to patients in 2005.
He said: "The change may seem small but it has a big effect.
"Writing to patients rather than about them changes the relationship between doctor and patient.
"It involves them more in their care and leads to all sorts of benefits.
"Millions of clinic letters are written every month in the NHS so this change could have a big impact."
The Royal College of GPs is also on board. Vice-chair Prof Kamila Hawthorne said: "I have seen a number of patients who have asked me to 'translate' the letter they have received from the hospital, which has been little more than a medical summary.
"By hospital doctors writing any letters directly to patients, with their GP copied in so we are always aware of what is happening regarding our patient's care, it should make the process more patient-centred, and make them feel more involved in their care, which will be beneficial for everyone."