- Latissimus dorsi
- Latissimus dorsi muscle
- Latrines
- Latrodectism
- Latrotoxin
- Latrunculin
- Lattice corneal dystrophy
- Lattice degeneration
- Laudanosine
- Laudanum
- Lauge-Hansen classification
- Laughter
- Laugier-Hunziker syndrome
- Laurdan
- Laurence-Moon syndrome
- Lauric acid
- Laurus nobilis
- Lavage
- Lavandula angustifolia
- Lavandulol
- Lavender oil
- Lawsone
- Laxatives
- Lazabemide
- Lazarus syndrome
- LcrV
- Le Chatelier's principle
- Lead abatement
- Lead and Copper Rule
- Lead aprons
- Lead citrate
- Lead compound
- Lead oxide
- Lead paint
- Lead poisoning
- Lead time bias
- Leaf protein concentrate
- Leaf spot
- Leafy
- Leaky gut syndrome
- Leaky scanning
- Lean body mass
- Lean body weight
- Learned helplessness
- Learned optimism
- Learning algorithms
- Learning disability
- Learning styles
- Learning theory
- Learning to learn
- Leber congenital amaurosis
- Leber's congenital amaurosis
- Leber's hereditary optic neuropathy
- Lebrikizumab
- Lecanoric acid
- Lecithin
- Lecithin cholesterol acyltransferase
- Lecithin sphingomyelin ratio
- Lecithinase
- Lectin pathway
- Lectins
- Ledderhose disease
- Ledipasvir
- Ledol
- Lee Silverman Voice Treatment
- Lefamulin
- Leflunomide
- Left anterior descending artery
- Left anterior fascicular block
- Left atrial appendage occlusion
- Left atrial enlargement
- Left atrial volume
- Left atrium
- Left axis deviation
- Left bundle branch block
- Left colic artery
- Left colic vein
- Left common carotid artery
- Left coronary artery
- Left gastric artery
- Left gastric vein
- Left marginal artery
- Left marginal vein
- Left pulmonary artery
- Left subclavian artery
- Left testicular vein
- Left ventricle
- Left ventricular hypertrophy
- Left ventricular thrombus
- Left-handedness
- Left-right asymmetry
- Leg
- Leg cramps
- Leg length inequality
- Leg raises
- Legal death
- Legal psychology
- Legionella
- Legionella pneumophila
- Legionellales
- Legionnaires' disease
- Legitimate peripheral participation
- Legius syndrome
- Legume lectin
- Legumes
- Leguminous plant
- Leigh syndrome
- Leigh's disease
- Leiomyoma
- Leiomyosarcoma
- Leishman stain
- Leishmania
- Leishmania braziliensis
- Leishmania donovani
- Leishmania infantum
- Leishmania major
- Leishmania tropica
- Leishmaniasis
- Leloir pathway
- Lemborexant
- Lemierre's syndrome
- Lemnisci
- Lemniscus
- Lenalidomide
- Length constant
- Length of stay
- Length time bias
- Lennox Gastaut Syndrome
- Lennox-Gastaut syndrome
- Lenograstim
- Lens
- Lens capsule
- Lens dislocation
- Lens distortion
- Lens placode
- Lens regeneration
- Lens subluxation
- Lenticonus
- Lenticulostriate arteries
- Lentiform nucleus
- Lentigines
- Lentiginosis
- Lentigo
- Lentigo maligna
- Lentigo maligna melanoma
- Lentils
- Lentinan
- Lentinula edodes
- Lentiviruses
- Lenvatinib