Summarize this article:

Making an herbal-infused oil consists of three parts: oil, your chosen herb, and heat. You need to choose an oil to be the base. You will infuse the herb into the oil to make your herbal oil. Make sure to use a high-quality, and preferably organic, oil. You can use virgin olive oil, safflower oil, castor oil, argan oil, or coconut oil. These can be found at local health stores, grocery stores, or online. When making your herbal oil, you have to decide which herb or herbs you want to use to make oil. Each batch will be a bit different because it depends on the season and the area from which the herbs have been gathered, the conditions around the time of harvest, and they type of herb you are using. You can use any of the herbs listed below, or any others that you grow or find.  Lavender. This oil is used for relaxation aromatherapy.  You can also use it to scent soaps.  Lavender has antimicrobial properties as well. Calendula. This is used as an anti-inflammatory and to promote wound healing. Cannabis. If this is legal in your area, you use it for anxiety and pain relief. It can also be used as an antispasmodic and anti-nausea agent. Garlic. This is primarily used in oils as an antibacterial agent.  Ginger root. Ginger is used as an anti-inflammatory agent.  Goldenseal. This is used as an anti-inflammatory agent. Mullein. Mullein is used for respiratory and ear infections. Rosemary. It can be used in aromatherapy and in soaps. Rosemary is often used as a nootropic, which increases cognitive abilities and memory. Rosemary oil is also used as a muscle relaxant and antispasmodic. Thyme. Thyme is used for respiratory infections and to calm coughs. Oregano. This is used as an antimicrobial agent and immune booster.  St John's wort. This is used as an antidepressant and to help get to and stay asleep.  Chamomile. This is used as a relaxant and sleep inducer.  Peppermint. Peppermint is used for digestive problems and irritable bowel syndrome. Eucalyptus. It is used for respiratory infections, sinusitis, and to calm coughs and relieve congestion. Most oils are measured out using a parts method for the ratio. This means you can easily adjust the amount of oil and herbs needed for the quantity of oil you want to make. Five parts of oil to one part herb is a very common ratio.  For example, you may put one tablespoon of dried herb for five tablespoons of base oil. The strength of the oil general is based on the length of time the oil infuses and the amount of heat used. However, each batch will probably be different due to factors of the herbs, including the growing and harvesting conditions or if it is fresh or dried. You can use herbal oils for so many different things. You can use them for natural medical treatments, cosmetics like hair care, face care, baby care, or body care, or even for cooking. Knowing how you will use the oil determines which base oil and herb you use.  For example, if you are going to use the oil for cooking, you may choose a high-quality extra virgin olive oil. If you want to use the oil for cosmetics, jojoba, coconut, or argan oil may be a better choice. Different oils have different properties, so knowing why you need the oil helps you choose your herb.
Decide on the base oil. Choose your herb. Use the right ratio. Decide how you will use your oil.