Section 2 of the Controlled Drugs and Substances Act states:
2. (1) In this Act,
“traffic” means, in respect of a substance included in any of Schedules I to IV,
- (a) to sell, administer, give, transfer, transport, send or deliver the substance,
- (b) to sell an authorization to obtain the substance, or
- (c) to offer to do anything mentioned in paragraph (a) or (b), otherwise than under the authority of the regulations.
The word "transport" is "not meant in the sense of mere conveying or carrying or moving from one place to another, but in the sense of doing so to promote the distribution of the narcotic to another.". 
In creating the offence relating to drug trafficking, Parliament did not mean to include buyers of drugs.
- R v Harrington,  1 CCC 189 (BCCA) at p 195
- R v Bienvenue, 2016 ONCA 865 (CanLII) at para 5
Offer to Sell
Trafficking by offer under s. 2(2)(c) only requires that the crown prove an intent to make the offer. It is not necessary to prove that the accused had an intent to follow through with the offer. As such, there is no need to prove that the accused had drugs on themselves at the time or was capable of fulfilling the request.
Trafficking by offer requires a) an offer to traffic in a narcotic and b) an intent to make an offer that will be taken as a genuine offer by the recipient.
The intent will depend on the presence of elements such as discussion of product, pricing and method of transaction.
R v Mamchur, 1978 CanLII 1813 (SK CA),  3 WWR 481 (SKCA) at p. 483
R v Jones, 1988 CanLII 4871 (SK CA), (1988) 74 Sask R. 4 (SKCA) at 10
R v Campbell, 1999 CanLII 676 (SCC),  1 SCR 565 at 25
R v Murdock, 2003 CanLII 4306 (ON CA), (2003), 176 CCC (3d) 232 (Ont. C.A.) at 14
R v Crain, 2012 SKCA 8 (CanLII)
R v Ralph, 2011 ONSC 3558 (CanLII),  O.J. No. 3156 (S.C.J.), aff’d on other grounds  O.J. No. 13 (C.A.)
e.g. R v Petrie,  O.W.N. 601 (C.A.)(*no link) -- drugs offered weren’t available;
R v Murdock, supra -- offer was withdrawn
R v Sherman,  5 W.W.R. 283 (BCCA)(*no link) -- offer was made for purpose of ripping buyer off
R v Reid 1996 CanLII 5213, (1996), 155 N.S.R. (2d) 368 (NSCA) -- no evidence that drugs were even available to seller
R v Brown (1953), 9 W.W.R. (N.S.) 701 (BCCA)(*no link) -- drugs not on the seller
R v Murdock, at p. 238
e.g. Ralph at para 38
R v Burke, 2014 ONSC 3199 (CanLII) at para 28
An observed hand-to-hand transaction may be evidence of drug trafficking. Such circumstantial evidence will only be probative if innocent explanations can be excluded.
R v N.O., 2009 ABCA 75 (CanLII) at para 41, 42
Aiding or Abetting Drug Buyers
Where the accused is not proven to have trafficked in drugs, the only other way that they can be liable for trafficking is if they are guilty as a party under s. 21(1)(b) or (c) for trafficking.
An "agent" for a purchaser or someone who "assists a purchaser to buy narcotics" will come into the definition of aiding or abetting under s. 21. This includes "bringing together the source of supply and the prospective purchaser". It will unlikely to be sufficient if the assistance is "rendered solely to the purchaser".
Opinion Evidence on Trafficking
To prove that someone was in possession of a controlled substance for the purpose of trafficking, the Crown must call expert evidence to given an opinion that the circumstances allow for the inference that the possessor intended to traffic.
See also: Expert Evidence for details on the law of expert evidence.
- E.g. See R v Balla, 2014 ABQB 127 (CanLII) at paras 50 to 62
Evidence of Intent
Amount of drugs
Trafficking can be inferred where the quantity/purity/value of drugs.
Where an accused is a user of drugs, there may be evidence suggestive that the drugs found in their possession may be consistent with personal use as opposed to trafficking. The amounts required to maintain the addiction and the habits of typical users are relevant. Either party is permitted to lead evidence concerning typical use, however, this usually takes the form of expert evidence.
The amount of drugs alone cannot be used to establish trafficking.
Marijuana amounts in the range of 3 pounds have been found to be unreasonable to be considered consumable for personal use. 
Cocaine amounts of 1kg have been found to be unreasonable to be for personal use.
Large quantities of unexplained wealth can allow a judge to lead to the conclusion of trafficking. This is particularly true where cash is in small denominations and is found near drugs.
Where packaging is found this may allow a judge to infer an intent to traffic. Packaging in numerous quantities, such as numerous small baggies, can create such an inference. 
R v Le, 2001 BCCA 658 (CanLII)
R v Adelberg, 2001 BCCA 637 (CanLII)
R v L'Huillier, 1997 CanLII 9606 (NB Q.B.)
R v Falahatchian, 1995 CanLII 941 (ON C.A.)
R v Naugler, 1994 ABCA 110 (CanLII)
- R v Petavel, 2006 BCSC 1931 (CanLII)
R v McCallum 2006 SKQB 287 (CanLII), (2006), 281 Sask.R. 272 at 28
R v Mehari, 2009 ABPC 217 (CanLII) at para 7
- R v Brophy (W.) (1971), 3 N.B.R.(2d) 594 (CA)(*no link)
- R v Wilcox, 2014 BCCA 65 (CanLII)
R v Alberts, 1999 CanLII 2246 (ON C.A.)
R v Le, 2001 BCCA 694 (CanLII)
R v Scott, 2003 CanLII 27446 (ON S.C.)
R v Kwok, 2002 BCCA 177 (CanLII)
R v Petavel, 2006 BCSC 1931 (CanLII)
A Dial-a-Dope operation is the manner in which drugs are often distributed to their customers. The seller and buyer will contact each other by phone and arrange to make an exchange at a pre-determined location.
The Crown will often adduce evidence to argue that the evidence suggests that such an operation was undertaken. This is determined by expert opinion of the evidence suggestive of such an operation.
Several cases have considered the methods of a dial-a-dope operation.