Lejía vs. cloro vs. lavandina vs. blanqueador
While the chemical compound sodium hypochlorite is the same, the word used to describe bleach in Spanish changes drastically depending on the region. Lejía, cloro, and lavandina are regional synonyms for the liquid disinfectant, whereas blanqueador is a descriptive term focusing on the action of whitening.
Lejía
B1This is the standard term used primarily in Spain and Peru to refer to liquid bleach. It is derived from the Latin word for lye or ashes used in washing.
Ten cuidado porque la lejía puede manchar tus pantalones negros.
(Be careful because bleach can stain your black pants.)
En España, es muy común limpiar el suelo del baño con lejía.
(In Spain, it is very common to clean the bathroom floor with bleach.)
Mi abuela siempre pone un poco de lejía en el agua para desinfectar las verduras.
(My grandmother always puts a little bleach in the water to disinfect vegetables.)
Cloro
B1Literally translating to the chemical element chlorine, this is the most common word for bleach in Mexico, Chile, Colombia, Venezuela, and most of Central America. While technically the element, in daily usage cloro implies the liquid cleaning product.
El olor a cloro en esta piscina es demasiado fuerte.
(The smell of chlorine in this pool is too strong.)
Mamá, se nos acabó el cloro para lavar la ropa blanca.
(Mom, we ran out of bleach to wash the white clothes.)
Por favor, compra una botella de cloro cuando vayas a la tienda.
(Please buy a bottle of bleach when you go to the store.)
Lavandina
C1This term is exclusively used in the Rioplatense region, specifically Argentina and Uruguay. It comes from the verb lavar (to wash) and refers to the standard household disinfectant.
Pasale un trapo con lavandina a la mesada de la cocina.
(Wipe the kitchen counter with a rag with bleach.)
La lavandina es esencial para matar todos los gérmenes en el hospital.
(Bleach is essential to kill all the germs in the hospital.)
No mezcles detergente con lavandina porque es peligroso.
(Do not mix detergent with bleach because it is dangerous.)
Blanqueador
B2This word translates literally to whitener. It is a neutral, descriptive term often found on product labels across all regions. It effectively refers to bleach when used for laundry, but can also refer to non-chlorine alternatives (oxygen bleach).
Para esta tela delicada, debes usar un blanqueador sin cloro.
(For this delicate fabric, you must use a bleach without chlorine.)
El dentista me recomendó un buen blanqueador para los dientes.
(The dentist recommended a good whitener for my teeth.)
Este detergente en polvo ya incluye blanqueador para las sábanas.
(This powder detergent already includes whitener for the sheets.)
Summary
To choose the right word, you must know your audience: use lejía in Spain, lavandina in Argentina/Uruguay, and cloro in most other parts of Latin America (especially Mexico). Use blanqueador if you are referring specifically to the product's ability to whiten clothes or reading a generic product label.