- Lablab purpureus
- Lactuca floridana
- Lactuca graminifolia
- Lactuca muralis
- Lactuca perennis
- Lactuca saligna
- Lactuca sativa
- Lactuca tatarica
- Lactuca viminea
- Lactuca virosa
- Lallemantia canescens
12.Lamium album
- Lathyrus aphaca
- Lathyrus cicera
- Lathyrus clymenum
- Lathyrus hirsutus
- Lathyrus latifolius
- Lathyrus nissolia
- Lathyrus odoratus
- Lathyrus palustris
- Lathyrus pratensis
- Lathyrus sylvestris
- Lathyrus tingitanus
- Lathyrus tuberosus
- Lathyrus vernus
- Laurus nobilis
- Lavandula dentata
- Lavandula multifida
- Lavatera arborea
- Lavatera cretica
- Lavatera trimestris
- Lawsonia inermis
- Lemna gibba
- Lemna minor
- Lemna trisulca
- Leonotis nepetifolia
- Leonurus cardiaca
- Leonurus sibiricus
- Leopoldia comosa
- Lepidium campestre
- Lepidium draba
- Lepidium latifolium
- Lepidium perfoliatum
- Lepidium ruderale
- Lepidium sativum
- Lepidium virginicum
- Lesser celandine
- Lettuce
- Leucanthemum vulgare
- Leucospermum hypophyllocarpodendron
- Leymus arenarius
- Liatris spicata
- Ligusticum scoticum
- Ligustrum vulgare
- Lilium bulbiferum
- Lilium canadense
- Lilium candidum
- Lilium chalcedonicum
- Lilium martagon
- Lilium pomponium
- Lilium superbum
- Lily of the valley
- Limodorum abortivum
- Limosella aquatica
- Linaria dalmatica
- Lindera benzoin
- Lindernia dubia
- Linnaea borealis
- Linum catharticum
- Linum flavum
- Linum narbonense
- Linum perenne
- Linum usitatissimum
- Lipandra polysperma
- Liparis liliifolia
- Liquidambar styraciflua
- Liquorice
- Lithospermum arvense
- Lithospermum officinale
- Lithospermum purpurocaeruleum
- Lobelia cardinalis
- Lobelia dortmanna
- Lobelia erinus
- Lobelia inflata
- Lobelia kalmii
- Lobelia siphilitica
- Lobelia urens
- Lobularia maritima
- Lolium perenne
- Lolium temulentum
- Long pepper
- Lonicera alpigena
- Lonicera caerulea
- Lonicera caprifolium
- Lonicera periclymenum
- Lonicera sempervirens
- Lonicera tatarica
- Lonicera xylosteum
- Lotus corniculatus
- Lotus maritimus
- Lotus tetragonolobus
- Ludwigia alternifolia
- Lunaria annua
- Lunaria rediviva
- Lupinus albus
- Lupinus angustifolius
- Lupinus luteus
- Lupinus perennis
- Luzula campestris
- Luzula pilosa
- Luzula spicata
- Lychnis chalcedonica
- Lychnis flos-cuculi
- Lycium barbarum
- Lycopodium annotinum
- Lycopodium clavatum
- Lycopodium obscurum
- Lycopus europaeus
- Lycopus virginicus
- Lysichiton camtschatcensis
- Lysimachia ciliata
- Lysimachia minima
- Lysimachia monelli
- Lysimachia nemorum
- Lysimachia nummularia
- Lysimachia punctata
- Lysimachia quadrifolia
- Lysimachia terrestris
- Lysimachia thyrsiflora
- Lysimachia vulgaris
- Lythrum hyssopifolia
- Lythrum portula
- Lythrum salicaria
Larrea divaricata
Chaparral (Larrea divaricata) and L. tridentata
- Usage: lots of things, including treating cancer.<wiki/List_of_medicinal_plants#cite_note-chaparral-61"> L. tridentata is often an ingredient in the quack cancer cure Cansema.
- Harmful effects: Chaparral is not effective for cancer and not known to be effective for anything else, either.<wiki/List_of_medicinal_plants#cite_note-chapcancer-62"> One CAM site claims it's good for lots of unrelated illnesses and only has "temporary unpleasant side effects",<wiki/List_of_medicinal_plants#cite_note-chaparral-61"> but, actually, it can cause fatal liver damage and kidney failure.<wiki/List_of_medicinal_plants#cite_note-chapcancer-62"> Other side effects may include fatigue, stomach pain, diarrhea, weight loss, fever, itching, rash, and allergic reactions.<wiki/List_of_medicinal_plants#cite_note-chapcancer-62"> Despite the title of that old cowboy serial, Chaparral cannot get you high.
Lobelia inflata
- Lobelia (Lobelia inflata)
- Used for: Asthma, bronchitis, cough, and smoking cessation.<wiki/List_of_medicinal_plants#cite_note-theherbbook-7"><wiki/List_of_medicinal_plants#cite_note-lob-148"> Not enough studies have been done to verify lobelia's effectiveness for any of these.
- Harmful effects: Side effects may include profuse sweating, nausea, vomiting, diarrhea, tremors, rapid heartbeat, mental confusion, convulsions, hypothermia, coma, and death.<wiki/List_of_medicinal_plants#cite_note-lob-148"> It's not called Indian Tobacco for nothing.