Hyperlipidaemia is the presence of abnormally high concentrations of lipids — cholesterol and triglycerides — in the blood plasma. Carried in lipoproteins (LDL, VLDL, HDL), excess lipids — particularly LDL cholesterol — infiltrate artery walls and drive atherosclerosis, the plaque buildup behind heart attacks and strokes. Causes divide into primary (inherited disorders like familial hypercholesterolaemia) and secondary: diets rich in saturated fat, obesity, diabetes, hypothyroidism, and excess alcohol. Diagnosis is the familiar lipid panel; treatment is lifestyle first — weight control, unsaturated fats for saturates, activity — then statins and newer agents for those at risk. Population-wide, lowering hyperlipidaemia has been among modern medicine’s great victories.