Health & Wellbeing The Medicinal Garden

Rosemary is aromatic and is often described to have a pinewood-like scent. It has many uses, ranging from the kitchen to aromatherapy.
Certain articles state that when the British first brought back rosemary in the ninth century, it was used in remedies that treat fever and toothaches. Later in the sixteenth century it was used to treat gout, loss of appetite, coughing and to prevent bad dreams. At one point it was even used as toothpaste!
Another added bonus is that all rosemary is edible. Do keep in mind there are many varieties of rosemary, each with their own flavours and opportunities. This is a general guide, please use caution and do your research before consuming any plant.

Growing rosemary
Rosemary is a heat and drought tolerant plant. The more sun, the more intense the aroma and flavour will be. Without enough sunlight the plant may struggle and become spindly.
Whilst free-draining soil is a must, rosemary is very hardy and can adapt to virtually any soil. Rosemary thrives best in a Mediterranean climate, with sandy soils
Rosemary does well in both containers and in the ground, making it very versatile. Whilst this is true, it's still recommended to be planted in ground. When planted in the ground it becomes very drought tolerant as it has roots that dig deep, accessing water deeper below the surface. When planted in a pot it may struggle to stay well hydrated, needing more frequent watering and also having to be cautious the container doesn't become waterlogged.
As a perennial plant, you can expect many years of joy.
Rosemary can grow very tall once established, up to 1,5m.

Addition by @JP 1983
Rosemary can easily be grown from cuttings. Snip off a decent, woody growing tip 15-20 cm long. Strip off the lower 10 cm of leaves and set the stem in a jar of water in a sunny spot. Change the water every 2 days. When the stem starts to put out roots after about 10 days, plant in your intended container or garden.

Health benefits
Rosemary is a rich in antioxidants and anti-inflammatory compounds, thought to help the immune system and blood circulation. In some places in Europe it's also used to help treat indigestion. And whilst more research is needed, some studies even suggest is may significantly help prevent brain aging.
There are studies showing that the carnosic and rosmarinic acids in rosemary have many beneficial properties. These can provide antibacterial, antiviral and antifungal properties. Consuming rosemary regularly can potentially help lower risks of infection and support the immune system.
Do use caution, as with anything, too much of something good can become a bad thing.

Uses​

Rosemary can be utilised in many ways, including fresh, dried and infused. The leaves are the part of the plant which are used for consumption reasons, as the stem can be rather woody and considered inedible. As a culinary herb, rosemary is often used to enhance meat dishes. The flowers are edible as well, often used in tea or salads.

Fresh it is often used in meal preparations. It is most popular in Mediterranean cuisine and compliments many foods, not limited by, soups, breads, stuffing, roasted vegetables, stews and meats.
The versatility of rosemary allows for it to be used in many ways, by seeping it in hot water for tea, to infusing in oil and rosemary butter. It can also be used for it's scent, being braided into rosemary wreaths,
By grabbing the top of the sprig of rosemary and sliding your fingers down the stem, the leaves can easily be removed. The sprig can be used as a skewer for kebabs on the grill.

Drying improves the length at which is can be stored. Dried rosemary is most often used for cooking or burning. It's fragrant scent also makes for the option of scent bags, such as rosemary dryer sachets.
Dried rosemary goes well in spice mixes, and can sometimes perform better than fresh rosemary when cooked for a longer period of time as fresh rosemary would lose it's "fresh" taste after being cooked for too long.

Infusing rosemary in oil allows you to use it in another number of things, edible and not. The oil can, for example, be used on popcorn, focaccia, potatoes, lamb chops, salmon and much more.
Infusing the oil can be done in many ways, both hot and cold. Some like to let it sit in the jar for over a month, before straining the rosemary out and using the oil in the kitchen.
Whilst you can infuse the rosemary on the stovetop, an even easier way is to use the crock pot. Remove the leaves from the stems of your (4) sprigs and add (2 cups of) olive oil. Let it cook on the highest setting for one to two hours, before letting it cool. After cooling for at least half an hour, you can strain the oil and put it in a container. It's recommended to keep the oil in an airtight container. After this process it can be stored for up to two months (six in the fridge).
The oil is great on foods, but also good for your hair and skin.

Rosemary compliments flavours, scents and herbs such as garlic, onion, lavender and thyme.

Further uses
Rosemary has a scent that is often considered to be calming which can promote better memory and focus. Because of this rosemary is often associated with positive memories and luck. Combined with other pleasant-smelling plants it may lower cortisol (stress hormone) levels and reduce anxiety. This can be done in many ways, by making wreaths, scent bags, dryer sachets and more.
Rosemary flowers can look amazing in flower arrangement. Cut rosemary is long-lasting and mixes well with many flowers.
Rosemary can even be used for oral uses, as it's antimicrobial properties make that it can kill of bad bacteria which can cause bad breath, tooth decay and gum diseases. This can be done by boiling or steeping rosemary sprigs along with some cloves until you are left with a potent homemade mouthwash. Rosemary oil can also be used alongside toothpaste to improve your oral health.
Rosemary is said to have pest controlling properties. By throwing some rosemary on the coals of your fire or BBQ, the smoke will help repel mosquitos.

Dangers
Whilst rosemary can be amazing and very versatile, there are still dangers attached to this plant. When consuming too much you can experience symptoms like an upset stomach, vomiting, intestinal irritation, kidney damage and more. As with any plant, it's recommended to proceed with a healthy amount of caution.