Trypan blue (trade name MembraneBlue, VisionBlue) is a vital stain used to selectively color dead tissues or cells blue. Live cells or tissues with intact cell membranes are not colored. Since cells are very selective in the compounds that pass through the membrane, in a viable cell trypan blue is not absorbed; however, it traverses the membrane in a dead cell. Hence, dead cells are shown as a distinctive blue color under a microscope. Since live cells are excluded from staining, this staining method is also described as a dye exclusion method. This dye may be a cause of certain birth defects such as encephalocele. Trypan blue is commonly used in microscopy (for cell counting) and in laboratory mice for assessment of tissue viability. The method cannot distinguish between necrotic and apoptotic cells. Trypan blue is also used in ophthalmic cataract surgery to stain the anterior capsule in the presence of a mature cataract, to aid in visualization, before creating the continuous curvilinear capsulorhexis.

Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO 2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. Generally it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, from paint to sunscreen to food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million metric tons. Titanium dioxide has excellent ultraviolet (UV) resistant qualities and acts as a UV absorbent. In the pharmaceutical industry, titanium dioxide is used in most sunscreens to block UVA and UVB rays, similar to zinc oxide. It is also commonly used as pigment for pharmaceutical products such as gelatin capsules, tablet coatings and syrups. In the cosmetics industry, it is used in toothpaste, lipsticks, creams, ointments and powders. It can be used as an opacifier to make pigments opaque. The FDA has approved the safety of titanium dioxide for use as a colorant in food, drugs and cosmetics, including sunscreens. However, controversy exists as to the safety of titanium dioxide nanoparticles used in the cosmetics industry, for example in sunscreens. Titanium and zinc oxides may be made into the nanoparticle size (0.2-100 nanometers) to reduce the white appearance when applied topically, but retain the UV blocking properties. Recent studies suggest titanium dioxide nanoparticles may be toxic, although further research is needed.

Isosulfan Blue is a synthetic visual lymphatic imaging agent. Injected into the periphery of the tumor site, isosulfan blue localizes to the lymphatic system and aids in the surgical identification of tumor sentinel nodes which stain blue. The chemical name of isosulfan blue is N-[4-[[4-(diethylamino)phenyl] (2,5-disulfophenyl) methylene]-2,5-cyclohexadien-1-ylidene]-N-ethylethanaminium hydroxide, inner salt, sodium salt. Isosulfan blue is a greenish blue color hygroscopic powder. Isosulfan blue injection 1% is a contrast agent for the delineation of lymphatic vessels. Isosulfan blue injection 1% upon subcutaneous administration, delineates lymphatic vessels draining the region of injection. It is an adjunct to lymphography in: primary and secondary lymphedema of the extremities; chyluria, chylous ascites or chylothorax; lymph node involvement by primary or secondary neoplasm; and lymph node response to therapeutic modalities.

Indigotindisulfonic acid (also known as Indigo carmine) is a synthetic dye discovered in 18th century. It is used in many countiries as a food colorant and a pH indicator. In medicine the dye is used to localize ureteral orifices during cystoscopy and ureteral catheterization. In June 2014 the FDA announced the shortage of indigotindisulfonic acid.

ICG is a cyanine fluorescent dye which is used in medicine as an indicator substance (for photometric hepatic function diagnostics and fluorescence angiography) in cardiac, circulatory, hepatic and ophthalmic conditions. It is administered intravenously and, depending on liver performance, is eliminated from the body with a half life of approx. 3-4 minutes.

Methylene blue, also known as methylthioninium chloride, is a medication from WHO's list of essential medicines. Upon administration, methylene blue is converted to leukomethylene blue by erythrocyte methemoblobin reductase in the presence of NADPH. Leukomethylene blue than reduces methemoglobin to oxyhemoglobin, thus restoring oxygen carrying capacity of the blood. Methylene blue is also used as a dye for various diagnostic procedures, for treatment of ifosfamide toxicity and for in vitro staining. Historically, it was used as a photosensitizer for photodynamic therapy for topical treatment of dermatologic or mucocutaneous infections, as an antidote for cyanide poisoning, but these applications are no longer approved. Methylene blue is investigated in clinical trials for treatment of septic shock and Alzheimer's disease.

Ferric chloride is a compound used as a food additive, a haemostatic or treatment for hypochromic anaemia. Ferric chloride induced vascular injury is a widely used model of occlusive thrombosis that reports platelet activation and aggregation in the context of an aseptic closed vascular system. Iron i.v. ferric chloride (960 mg) has being shown to be effective in correcting anaemia in HD patients with iron deficiency.