On Monday, 12 January 2026, between 07:00 and 10:00 CET (Amsterdam time), this website will be unavailable due to scheduled maintenance.
This resource focuses on side effects and other terms used in medicines information and assessments of medicines. It does not include terms that are used only rarely, nor does it cover most disease states or technical terms.
How to use EMA’s medical terms simplifier
- You can search for a term or click on a letter below to see terms beginning with that letter.
- Each entry contains a short description. For some, a longer or alternative description is available by selecting the term.
- We use ‘< >’ to indicate alternative or optional wording.
EMA’s medical terms simplifier will be updated periodically. For comments or suggestions, you can use our Medical terms simplifier comments form.
E
-
Ecchymosis
bruise -
Echocardiography
a diagnostic test where an image of the heart is obtained using ultrasound -
Ectopia lentis
a disorder where the lens of the eye is in the wrong position -
Ectopic pregnancy
pregnancy developing outside the womb -
Eczema
itchy, red and dry skin -
Eczema, atopic
itchy, red and dry skin in people prone to allergies -
Efficacy
1) effectiveness; 2) how well <X><a medicine> works in clinical studies -
Ejection fraction
how much blood is pumped out of the heart in one beat -
Electrocardiogram (ECG)
a test of the heart’s <electrical> activity -
Electrolytes
salts such as sodium, potassium, calcium, chloride and bicarbonate <in blood and other fluids in the body> -
Embolisation
a procedure to block a blood vessel <to stop bleeding or to block the flow of blood to a tumour or abnormal cells> -
Embolism
obstruction of a blood vessel <by a clot> -
Embolism, air/gas
air or gas bubbles in the blood that obstruct a blood vessel -
Emetogenic
triggering nausea and vomiting -
Emotional lability
mood swings -
Empirical treatment
treatment started on current knowledge until better information is available -
Encephalitis
inflammation of the brain -
Encephalopathy
brain disorder caused by a harmful substance or infection -
Encephalopathy, hepatic
brain damage caused by liver problems -
Encephalopathy, hyperammonaemic
brain damage caused by high levels of ammonia -
Endocarditis
infection of the sac around the heart <which can lead to serious heart complications> -
Endocrine
1) related to <glands that produce> hormones in the body; 2) hormonal -
Endometrium
the lining of the womb -
Endophthalmitis
inflammation of the inside the eye <often caused by infections> -
Endoscope
a flexible device used to look inside body cavities -
Endoscopy
a procedure that uses a tube with a camera to look inside the body -
Engraftment
when the cells start growing <and producing normal blood cells> -
Enzyme
a protein that helps specific chemical processes in the body -
Enzyme replacement therapy
therapy in which the patient is provided the enzyme that is lacking -
Eosinophil
a type of white blood cell -
Eosinophilia
an excess of eosinophils, a type of white blood cell -
Epidemic
when a disease spreads to a large number of people in a community, region or country -
Epidemiological studies
studies of the causes and distribution of diseases in the population -
Epidermis
outer layer of the skin -
Epigastralgia
pain around the upper part of the stomach -
Epigastric (region)
upper and middle part of the belly -
Epiphyses
the growing ends of long bones <which become part of the main bone when growth finishes> -
Epistaxis
nosebleed -
Erectile dysfunction
inability to get or keep an erection; impotence -
Erosion
ulcer -
Eructation
belching -
Erythema
reddening of the skin -
Erythropoietin
hormone that stimulates the production of red blood cells <by the bone marrow> -
Event-free survival
[used in cancer trials] how long patients live without <a complication or sign of disease occurring or coming back> <their disease coming back> -
Exacerbation
flare-up -
Exercise capacity
the ability to carry out physical activity -
Exfoliative
flaky -
Extracorporeal membrane oxygenation (ECMO)
a technique to oxygenate the blood outside the body using a device similar to a heart-lung machine -
Extrapyramidal side effects/symptoms
effects on a part of the brain that regulates movement <which may result in tremor, muscle spasms or movement disorders> -
Extravasation
when a medicine that is normally injected into a vein leaks or is accidentally injected into the tissue surrounding the vein, where it can cause serious damage