These recommendations are consistent with those made by the Institute for Clinical Systems Improvement [ICSI, 2004] and are mainly based on consensus statements and reports, narrative reviews, and medical opinion. The treatments recommended in this section are generally not suitable for investigation by randomized controlled trials (RCTs), owing to practical and economic reasons.

• Increased fluid intake. Despite being almost universally recommended, very little evidence supports increased fluid intake in the common cold. A Cochrane review (search date: July 2005) investigated this intervention but found no controlled trials suitable for inclusion [Guppy et al, 2005]. The author commented that limited evidence from observational studies suggested that too much fluid could be dangerous, especially in young children. Nevertheless, it is important to keep the body hydrated at all times, and as fluid loss is likely to be greater when fever and nasal discharge are present, it is prudent to drink more fluid than normal.
• Diet. There is no proof that specific diets are beneficial in people with the common cold. Furthermore, the available evidence from RCTs does not support the use of high doses of vitamins or minerals.
• Rest. At present, there is no evidence on whether rest is beneficial for the common cold. The best advice available is that people should remain as active as they can without feeling significant discomfort.
• Symptomatic remedies. In general, evidence to support the use of symptomatic remedies is lacking, but this does not necessarily mean they are ineffective, and anecdotal reports support their use. In general, it is thought to be better to use safe traditional remedies than to use ineffective over-the-counter medicines:
• Steam inhalation is reputed to reduce nasal decongestion by loosening mucous and inhibiting virus replication. The efficacy of steam inhalation was the subject of a Cochrane review (search date: December 2005) which identified six trials of the intervention [Singh, 2006]. Most of the trials reported positive outcomes, with an overall symptom relief risk reduction of 0.56 (95% CI 0.40 to 0.79). However, the authors warned of the dangers of steam inhalation, in particular scalding in young children.
• Vapour rubs have been shown to be beneficial in children with bronchitis [Berger et al, 1978], but evidence for their efficacy in the common cold is lacking. However, some children like the sensation of the rub and may experience a degree of symptom relief.
• Gargling with salt water has not been shown to be effective by any study, but there are anecdotal reports that it may soothe a sore throat, and it is unlikely to be harmful.
• Menthol lozenges have little effect on nasal congestion using objective measurements, but they may create the sensation of improved airflow and therefore create a subjective improvement [Eccles et al, 1990].
• Saline nasal drops are thought to facilitate mucous drainage from the nose, but there are no controlled trials to verify this [MHRA, 2009].