German chamomile essential oil is extracted from Matricaria chamomilla (M. recutica) of the same family and is also known by the names of blue chamomile, Hungarian chamomile and single chamomile.
Both Roman and German chamomile have excellent calming properties, but Roman chamomile is more effective for irritation, impatience and feeling disagreeable, and has great value in treating PMS and other menstrual and menopausal problems, while German chamomile  is superbly effective on the skin, not only to sooth and calm, but to heal and for tissue regeneration. 
 
Oil properties
The Roman chamomile essential oil has a sweet, apple-like fragrance and is very light clear blue in color with a watery viscosity, while the German chamomile oil has a sweet, straw-like fragrance, is dark blue in color and its viscosity is medium.
Origin of Roman and German chamomile oil 
German chamomile oil is mostly cultivated in Hungary, Egypt, Eastern Europe and France, while Roman chamomile is cultivated in Germany, France, Spain, Italy, Morocco and France.
Roman chamomile is a small perennial herb, with a hairy stem and feathery pinnate leaves, daisy like white flowers (larger than those of German chamomile) and grows about 25 cm high, while German chamomile grows about 60 cm high and has a hairless branching stem, with delicate feathery leaves and simple daisy like white flowers on single stems.
To the Egyptians it was a herb dedicated to the sun, to cure fevers, and to the moon, for its cooling ability. It was also recognized as a soother of nervous complaints and was used in shampoos, cosmetics and perfumes.
German chamomile contains azulene, a powerful anti-inflammatory agent. This blue crystal is not actually present in the plant, but forms in the oil and only a small quantity is needed to be effective.
Both chamomile oils are extracted from the flowers by steam distillation, with the Roman chamomile yielding about 1.7 % from fresh flowers and German chamomile yielding about 0.2 - 0.4 %.
Chemical composition
The main chemical components of Roman chamomile oils are a-pinene, camphene, b-pinene, sabinene, myrcene, 1,8-cineole, y-terpinene, caryophyllene, and propyl angelate and butyl angelate.
The main constituents of German chamomile oil are chamazulene, a-bisabolol, bisabolol oxide A, bisabolol oxide B and bisabolone oxide A.
Precautions
Both types of chamomile oil are considered non-toxic and non-irritant, yet since they do have emmenagogue properties when used in high concentrations, they should be avoided during pregnancy.
 Therapeutic properties
The therapeutic properties of Roman chamomile oil are analgesic, anti-spasmodic, antiseptic, antibiotic, anti-inflammatory, anti-infectious, anti-depressant, anti-neuralgic, antiphlogistic, antiseptic, antispasmodic, bactericidal, carminative, cholagogue, cicatrisant, emmenagogue, febrifuge, hepatic, sedative, nervine, digestive, tonic, sudorific, stomachic, vermifuge and vulnerary.
The therapeutic properties of German chamomile oil on the other hand are analgesic, anti-allergenic, anti-spasmodic, antibiotic, anti-inflammatory, antiphlogistic, bactericidal, carminative, cicatrisant, cholagogue, emmenagogue, hepatic, digestive, sedative, stomachic, vermifuge, vasoconstrictor and vulnerary.
Roman chamomile oil is used for
This essential oil can be used with great effect on children when they feel irritable, impatient, teething or colicky. Women find it great to relieve PMS. In general it is good for abdominal pain, gall bladder problems, as well as for throat infections. it furthermore helps to relieve allergies, hay fever and asthma.
For the skin, it can be used to calm acne, eczema, rashes, wounds, dermatitis, dry and itchy skin and other allergic conditions in general.
For babies it can be used in a very diluted form to sooth an irritated and teething baby and helps for colic, diarrhea and gastric spasms.
German chamomile oil is used for
This essential oil has a calming effect on the mind and body and is excellent in treating any type of inflammation - be that internal or external - and is very effective on urinary stones (bladder gravel) as well. It stimulates the liver and gall bladder, thereby improving digestion and is valuable in treating menstrual and menopausal problems.
On the skin, it is a miracle worker and calms red, dry and irritated skin, as well as calming allergies, eczema, psoriasis and all other flaky skin problems. It is high in -(-a)-bisabolol which promotes granulation (healing) and is also a great tissue regenerator.
Summary
Both Roman and German chamomile have  calming and relaxing abilities, especially on the nervous and digestive systems, regulating and easing the menstrual cycle. They have soothing and healing influence on the skin, as well as being a potent remedy for inflammatory conditions.
Burners and vaporizers
Roman chamomile can be used in vapor therapy, for nervous complaints, headaches and migraines.
Blended massage oil or in the bath
Roman chamomile can be used in a blended massage oil, or diluted in the bath, to assist with allergies, anorexia, addiction, colic, insomnia, back pain, muscle pain, arthritis, post-natal depression and bowel disorders, whereas German chamomile can be used for asthma, measles, mumps, PMS, menopausal symptoms, as well as rheumatism.
Lotion and cream
Roman chamomile can be used in a cream base for diaper rash, burns and sunburn, while German chamomile is useful in general skincare, especially in treating allergic skin.
Mouthwash
Roman chamomile can be used as a mouthwash for dental abscesses and tonsillitis.
chamomile blends well with
Both chamomiles blend well with bergamot, clary sage, lavender, geranium,jasmine, tea tree, grapefruit, rose, lemon and ylang-ylang.